DNA imaging and visualization techniques are crucial in biological experiments and have also emerged as a powerful method for single-molecule studies.Traditional intercalating dyes(e.g.,SYTOX,EtBr,GelRed)can stain DNA...DNA imaging and visualization techniques are crucial in biological experiments and have also emerged as a powerful method for single-molecule studies.Traditional intercalating dyes(e.g.,SYTOX,EtBr,GelRed)can stain DNA but may alter its structure and mechanical properties,and cause photocleavage.Recently,a novel fluorescent DNA-binding protein(FP-DBP)was introduced,which can stain DNA without sequence preference and without inducing photocleavage.In this study,using a custom-built magnetic tweezers system,we performed DNA stretching,twisting and unzipping experiments to compare the mechanical properties of DNA with and without two kinds of intercalating dyes(SYTOX Orange and GelRed)and mCherry FP-DBP.Our results show that mCherry FP-DBP does not affect DNA structure or mechanics,unlike SYTOX Orange and GelRed,making FP-DBP a promising tool for DNA visualization in single-molecule experiments.展开更多
The onset of amyotrophic lateral sclerosis is usually characterized by focal death of both upper and/or lower motor neurons occurring in the motor cortex,basal ganglia,brainstem,and spinal cord,and commonly involves t...The onset of amyotrophic lateral sclerosis is usually characterized by focal death of both upper and/or lower motor neurons occurring in the motor cortex,basal ganglia,brainstem,and spinal cord,and commonly involves the muscles of the upper and/or lower extremities,and the muscles of the bulbar and/or respiratory regions.However,as the disease progresses,it affects the adjacent body regions,leading to generalized muscle weakness,occasionally along with memory,cognitive,behavioral,and language impairments;respiratory dysfunction occurs at the final stage of the disease.The disease has a complicated pathophysiology and currently,only riluzole,edaravone,and phenylbutyrate/taurursodiol are licensed to treat amyotrophic lateral sclerosis in many industrialized countries.The TAR DNA-binding protein 43 inclusions are observed in 97%of those diagnosed with amyotrophic lateral sclerosis.This review provides a preliminary overview of the potential effects of TAR DNAbinding protein 43 in the pathogenesis of amyotrophic lateral sclerosis,including the abnormalities in nucleoplasmic transport,RNA function,post-translational modification,liquid-liquid phase separation,stress granules,mitochondrial dysfunction,oxidative stress,axonal transport,protein quality control system,and non-cellular autonomous functions(e.g.,glial cell functions and prion-like propagation).展开更多
Theoretical studies on the electronic and geometric structures, the trend in DNA-binding affinities as well as the the structure-activity relationship （SAR） of a series of water-soluble Ru（II） methylimidazole comp...Theoretical studies on the electronic and geometric structures, the trend in DNA-binding affinities as well as the the structure-activity relationship （SAR） of a series of water-soluble Ru（II） methylimidazole complexes, i.e. [Ru（Mehn）4iip]^2＋ （1） （MeIm=l-methylimidazole, iip=2-（1H-imidazo-4-group）-lH-imidazo[n,5-f][1,10]phenanthroline）, [Ru（MeIm）4tip]^2＋ （2） （tip=2-（thiophene-2-group）-lH-imidazo[4,5-f] [i,10]phenanthroline）, and [Ru（Melm）42ntz]^2＋ （3） （2ntz=2-（2-nitro-l,3-thiazole-5-group）-lH-imidazo[4,5-f][1,10]phenanthroline）, were car- ried out using the density functional theory （DFT）. The electronic structures of these Ru（II） complexes were analyzed on the basis of their geometric structures optimized in aqueous solution, and the trend in the DNA-binding constants （Kb） was reasonably explained. The results show that the replacement of imidazole ligand by thiophene ligand can effectively improve the DNA-binding affinity of the complex. Meanwhile, it was found that introduc- ing the stronger electronegative N atom and NO2 group on terminal loop of intercalative ligand can obviously reduce the complex＇s LUMO and HOMO-LUMO gap energies. Based on these findings, the designed complex [Ru（MeIm）42ntz]^2＋ （3） can be expected to have the greatest Kb value in complexes 1-3. In addition, the structure-activity relationships and antitumor mechanism were also carefully discussed, and the antimetastatic activity of the designed complex 3 was predicted. Finally, the electronic absorption spectra of this series of complexes in aqueous solution were calculated, simulated and assigned using DFT/TDDFT methods as well as conductor-like polarizable continuum model （CPCM）, and were in good agreement with the experimental results.展开更多
We have developed an on-line detection method using acridine orange as the fluorescence probe and applied this method to rapidly identify active compounds in herbal medicines. This on-line method was equipped with a h...We have developed an on-line detection method using acridine orange as the fluorescence probe and applied this method to rapidly identify active compounds in herbal medicines. This on-line method was equipped with a high-performance liquid chromatography tandem diode array detector, electrospray ionization-ion-trap time-of-flight mass spectrometry and DNA- acridine orange fluorescence detection （HPLC-DAD-MSn-DNA-AO-FLD）. A large amount of information could be simultaneously obtained during one run, which included HPLC fingerprint, ultraviolet spectra, total ion chromatograms, MSn data of high-resolution mass spectrometry and activity profile of each compound binding with DNA. The method also provided information on structureactivity relationships and mechanism of interaction. We used this on-line method to identify five DNA-binding activity components from Lithospermum erythrorhizon sample for the first time. The result showed that the parent nucleus of shikonin derivatives could bind with DNA. The structure-activity relationship showed that the parent nucleus of shikonin derivatives plays a major role in DNA binding, not the carboxyl group on the side chain. This simple, rapid, high precision and good stability on-line method should be useful for compound separation, structural identification and screening of DNA-binding compounds in herbal medicines.展开更多
A sensitive approach for the qualitative detection of DNA-binding protein on the microarray was developed. DNA complexes in which a partial duplex region is formed from a biotin-primer and a circle single strand DNA ...A sensitive approach for the qualitative detection of DNA-binding protein on the microarray was developed. DNA complexes in which a partial duplex region is formed from a biotin-primer and a circle single strand DNA （ssDNA） were spotted on a microarray. The endonuclease recognition site （ERS） and the DNA-binding sites （DBS） were arranged side by side within the duplex region. The working principle of the detection system is described as follows： when the DNA-binding protein capture the DBS, the endonuclease could not attach to the ERS, and the immobilized primer in the DNA complex could be extended along the circle ssDNA by rolling circle amplification （RCA）. When no protein protects the DBS, the ERS could be attacked by the endonuclease and subsequently no rolling circle amplification occurs. Thereby we can detect the sequence specific DNA-binding activity with high-sensitivity due to the signal amplification of RCA.展开更多
A new cobalt(Ⅱ) complex with tridentate ligand 2, 6-bis (benzimidazol- 2-yl)pyridine has been synthesized by microwave irradiation method and characterized by elemental analysis, electrochemical and spectral methods....A new cobalt(Ⅱ) complex with tridentate ligand 2, 6-bis (benzimidazol- 2-yl)pyridine has been synthesized by microwave irradiation method and characterized by elemental analysis, electrochemical and spectral methods. The binding of the complex with calf thymus DNA has also been investigated by absorption and fluorescence spectra.展开更多
Two silver（I）-sulfonate complexes,[Ag（NO3）（4,4＇-bipy）][Ag（HL）（4,4＇-bipy）]·2H2O（1） and[Ag（H2O）（4,4＇-bipy）][AgL（4,4＇-bipy）]·2H2O（2）,have been synthesized by in situ reaction（H2L = 2-fo...Two silver（I）-sulfonate complexes,[Ag（NO3）（4,4＇-bipy）][Ag（HL）（4,4＇-bipy）]·2H2O（1） and[Ag（H2O）（4,4＇-bipy）][AgL（4,4＇-bipy）]·2H2O（2）,have been synthesized by in situ reaction（H2L = 2-formylbenzenesulfonic acid,4,4-bipy = 4,4-bipyridine）.1 displays two parallel 1D chains expending to a 3D supramolecule by n—n interactions and O-H…O hydrogen bonds,in which the[Ag（NO3）]or[Ag（HL）]units are joined by bridging 4,4＇-bipy molecules,respectively.The interactions between the complexes and DNA were studied by means of fluorescence spectra and surface-enhanced Raman scattering（SERS） spectra.The special configuration and intercalation effects between 1 and DNA are stronger than that between 2 and DNA.展开更多
Two novel polypyridyl{PylP=2-(pyren-1-yl)-lH-imidazo[4,5-f][1,10]phenanthroline,bpy=2,2′-bipyridine,dmb=4,4′-dimethyl-2,2′-bipyridine}ruthenium(Ⅱ)complexes[Ru(bpy)_(2)(PyIP)]^(2+)(1)and[Ru(dmb)_(2)(PyIP)]^(2+)(2)h...Two novel polypyridyl{PylP=2-(pyren-1-yl)-lH-imidazo[4,5-f][1,10]phenanthroline,bpy=2,2′-bipyridine,dmb=4,4′-dimethyl-2,2′-bipyridine}ruthenium(Ⅱ)complexes[Ru(bpy)_(2)(PyIP)]^(2+)(1)and[Ru(dmb)_(2)(PyIP)]^(2+)(2)have been synthesized and characterized by elemental analysis,ES-MS and a H NMR spectroscopy.The DNA-binding of these complexes were investigated by spectroscopic methods and viscosity measurements.The experimental results indicate that both complexes 1 and 2 bind to calf thymus DNA in classical intercalation mode,and however,complex 1 intercalated more strongly than complex 2,due to the different ancillary ligands.展开更多
A complex [Cd2Na2（BOABA）2（H2O）8]·H2O（1） was synthesized by using 2,4-bisoxyacetate-benzoic acid（H3BOABA） and Cd（OH）2. It was characterized by elemental analysis, IR spectra, and single-crystal X-ray dif...A complex [Cd2Na2（BOABA）2（H2O）8]·H2O（1） was synthesized by using 2,4-bisoxyacetate-benzoic acid（H3BOABA） and Cd（OH）2. It was characterized by elemental analysis, IR spectra, and single-crystal X-ray diffraction. Complex 1 shows a two-dimensional 3-connected rigid plane. The interactions between the ligand and its complex with DNA were studied by Et Br fluorescence probe. Photoluminescent studies indicate that the complex may be excellent candidates for potential photoactive materials.展开更多
The WRKY proteins are a family of plant-specific transcription factors(TFs)that are widely involved in plant development and anti-stress responses.Arabidopsis WRKY11(AtWRKY11)functions in regulating plant defense agai...The WRKY proteins are a family of plant-specific transcription factors(TFs)that are widely involved in plant development and anti-stress responses.Arabidopsis WRKY11(AtWRKY11)functions in regulating plant defense against abiotic stress and belongs to the Ild subgroup of WRKY TFs.We herein report the expres sion,purification and preliminary structural characterization of AtWRKY11 DNA-binding domain(DBD)using solution NMR Almost complete backbone chemical shift assignments of AtWRKY11-DBD have been ob-tained.Chemical shift-based secondary structure analysis suggests that AtWRKY11-DBD may exhibit local conformational diferences from the X-ray structure of the C-terminal WRKY domain of AtWRKY1,particularly in the β1 and β5 strands.Our current study provides the basis for further structural and interactional studies.展开更多
Enterovirus A71(EV-A71)is one of the etiological pathogens leading to hand,foot,and mouth disease(HFMD),which can cause severe neurological complications.The neuropathogenesis of EV-A71 infection is not well understoo...Enterovirus A71(EV-A71)is one of the etiological pathogens leading to hand,foot,and mouth disease(HFMD),which can cause severe neurological complications.The neuropathogenesis of EV-A71 infection is not well understood.The mislocalization and aggregation of TAR DNA-binding protein 43(TDP-43)is the pathological hallmark of amyotrophic lateral sclerosis(ALS).However,whether TDP-43 was impacted by EV-A71 infection is unknown.This study demonstrated that TDP-43 was cleaved during EV-A71 infection.The cleavage of TDP-43 requires EV-A71 replication rather than the activated caspases due to viral infection.TDP-43 is cleaved by viral protease 3 C between the residues 331 Q and332 S,while mutated TDP-43(Q331 A)was not cleaved.In addition,mutated 3 C which lacks the protease activity failed to induce TDP-43 cleavage.We also found that TDP-43 was translocated from the nucleus to the cytoplasm,and the mislocalization of TDP-43 was induced by viral protease 2 A rather than 3 C.Taken together,we demonstrated that TDP-43 was cleaved by viral protease and translocated to the cytoplasm during EV-A71 infection,implicating the possible involvement of TDP-43 in the pathogenesis of EV-A71 infection.展开更多
A bismuth（Ⅲ） complex 1 （H2-4,4＇-bipy）[Bi（HPPA）5]（H2PPA）.4H2O （H2PPA = p- hydroxy- phenylacetic acid, 4,4＇-bipy = 4,4＂-bipyridyl） was hydrothermally synthesized from p-hydroxy-phenylacetic acid （H2PPA）,...A bismuth（Ⅲ） complex 1 （H2-4,4＇-bipy）[Bi（HPPA）5]（H2PPA）.4H2O （H2PPA = p- hydroxy- phenylacetic acid, 4,4＇-bipy = 4,4＂-bipyridyl） was hydrothermally synthesized from p-hydroxy-phenylacetic acid （H2PPA）, Bi（NO3）3＂6H20 and 4,4＇-bipyridyl, and characterized by elemental analysis, IR, molar conductivity and TG. The single-crystal X-ray diffraction studies demonstrated that the complex is of monoclinic system, space group P21 with a = 10.928（7）, b = 22.558（7）, c = 11.313（7） A, β = 91.864（4）°, V = 2787.7（4） A3, Z = 2, C58H61BiN2O22, Mr = 1347.07, F（000） = 1364, Dc= 1.605 g/cm-3, p（MoKa） = 3.247 mm-1, the final R = 0.0269 and wR = 0.0540 for 9776 observed reflections with I 〉 2or（I）. The bismuth（I/I） is seven-coordinated with O atoms, forming a monocapped octahedral geometry. Complex 1 further forms a 3D supramolecular architecture by hydrogen bonds and π-π stacking interactions. Moreover, the interaction between the complex and DNA was studied by EtBr fluoescent probe.展开更多
GATA-6 mRNA utilizes two Met-codons in frame as translational initiation codons in cultured mammalian cells. Deletion of the nucleotide sequence encoding the PEST sequence between the two initiation codons unusually r...GATA-6 mRNA utilizes two Met-codons in frame as translational initiation codons in cultured mammalian cells. Deletion of the nucleotide sequence encoding the PEST sequence between the two initiation codons unusually reduced the protein molecular size on SDS-polyacrylamide gel-electrophoresis. The reduced molecular size is ascribed to the molecular property of GATA-6, since both amino-and carboxy-lterminal tags introduced into GATA-6 were detected on the gel. This PEST sequence seems to contribute to expansion of the long-type GATA-6 molecule. The long-type GATA-6 containing the PEST sequence exhibits more activation potential than that without this sequence, the latter’s activity being similar to that of the short-type GATA-6. We further demonstrated that human colon and lung cancer cell lines express both the long-type GATA-6 and the short-type GATA-6 in their nuclei.展开更多
Transcription factor SPI is a protcin present in mammalian cells that binds to GC box promoter clements of Gene and selectively activates mRNA synthesis. The gene contains functional recognition sites. It contains thr...Transcription factor SPI is a protcin present in mammalian cells that binds to GC box promoter clements of Gene and selectively activates mRNA synthesis. The gene contains functional recognition sites. It contains three continuous zinc finger motifs, which are believed being mctalloprotein structures that interact with DNA. We synthesized the second zine finger fragment of SP1 (SP1-ZF2) and its mutant (SP1-ZF2 / HT. E20→H. R23→T), we also synthesized the Cys-Cys loop (ZF6) and the His-His loop (ZF5) of SPI and linked the twoloops together using a β-turn structure to obtain a finger mimic analogue (ZF-15) by stepwise solid-phase technique. Atomic absorption studies show that SP 1-ZF2 and SP1-ZF2 / HT bind zinc cquimolarly, but ZF-15 docs not bind Zn anyway. The CD experiments demonstrate a significant change in secondary structure in the prescnce or absence of Zn to SP1-ZF2 and SP1-ZF2/ HT, but there is no change about ZF-15. Gcl-retardation clectrophoresis assays indicate that SP1-ZF2 binds to DNA sequence specifically in the presence of Zn, but SP1-ZF2 / HT docs not bind as SP 1-ZF2 did. We observed that a single zine finger like SP1-ZF2 is able to bind DNA sequence specifically.展开更多
Three mononuclear oxovanadium complexes [VO(Hbid)(CF3PIP)] (1) (Hbid=(E)-2-(2-hydroxybenzylideneamino) isoindoline-1,3-dione, CF3PIP=2-(2-trifluoromethyl phenyl)imidazole[4,5-f][1,10] phenanthroline), [VO(Hbid)(m-CF3P...Three mononuclear oxovanadium complexes [VO(Hbid)(CF3PIP)] (1) (Hbid=(E)-2-(2-hydroxybenzylideneamino) isoindoline-1,3-dione, CF3PIP=2-(2-trifluoromethyl phenyl)imidazole[4,5-f][1,10] phenanthroline), [VO(Hbid)(m-CF3PIP)];(2) (m-CF3PIP=2-(3-trifluoromethyl phenyl)imidazole [4, 5-f][1,10]phenanthroline) and [VO(Hbid)(p-CF3PIP)];(3) (p-CF3PIP=2-(4-trifluoromethyl phenyl) imidazole[4,5-f][1,10]phenanthroline) have been synthesized and characterized by elemental analysis, IR, molar conductance, ES-MS and 1H NMR. The DNA-binding properties of these complexes were studied by using UV-Vis absorption titration, fluorescence spectra, viscosity measurements and thermal denaturation studies. The results show that 1, 2 and 3 interact with calf thymus DNA (CT-DNA) by intercalation modes and the magnitude of their intrinsic binding constants (Kb values) follows the order: 2 < 1 < 3. Furthermore, their photocleavage properties with pBR322 plasmid DNA were investigated by agarose gel electrophoresis experiments. The DNA cleavage capacity of complex 3 is also stronger than that of 1 and 2.展开更多
Cryptochromes are blue light photoreceptors that mediate various light responses in plants and mammals. The heterotrimeric G-protein is known to regulate various physiological processes in plants and mammals. In Arabi...Cryptochromes are blue light photoreceptors that mediate various light responses in plants and mammals. The heterotrimeric G-protein is known to regulate various physiological processes in plants and mammals. In Arabidopsis, cryptochrome 1(CRY1) and the G-protein β subunit AGB1 act antagonistically to regulate stomatal development.The molecular mechanism by which CRY1 and AGB1 regulate this process remains unknown.Here, we show that Arabidopsis CRY1 acts partially through AGB1, and AGB1 acts through SPEECHLESS(SPCH), a master transcription factor that drives stomatal initiation and proliferation, to regulate stomatal development. We demonstrate that AGB1 physically interacts with SPCH to block the b HLH DNA-binding domain of SPCH and inhibit its DNA-binding activity. Moreover, we demonstrate that photoexcited CRY1 represses the interaction of AGB1 with SPCH to release AGB1 inhibition of SPCH DNA-binding activity, leading to the expression of SPCH-target genes promoting stomatal development. Taken together, our results suggest that the mechanism by which CRY1 promotes stomatal development involves positive regulation of the DNA-binding activity of SPCH mediated by CRY1 inhibition of the AGB1-SPCH interaction. We propose that the antagonistic regulation of SPCH DNA-binding activity by CRY1 and AGB1 may allow plants to balance light and G-protein signaling and optimize stomatal density and pattern.展开更多
Plant NLR proteins enable the immune systemto recognize and respond to pathogen attack.An early consequence of immune activation is transcriptional reprogramming.SomeNLRs have been shownto act in the nucleus and inter...Plant NLR proteins enable the immune systemto recognize and respond to pathogen attack.An early consequence of immune activation is transcriptional reprogramming.SomeNLRs have been shownto act in the nucleus and interact with transcription factors.The Rx1 NLR protein of potato binds and distorts doublestranded DNA.However,the components of the chromatin-localized Rx1 complex are largely unknown.Here,we report a physical and functional interaction between Rx1 and NbDBCP,a bromodomaincontaining chromatin-interacting protein.NbDBCP accumulates in the nucleoplasmand nucleolus,interacts with chromatin,and redistributes Rx1 tothe nucleolus in a subpopulation of imaged cells.Rx1 overexpression reduces the interaction between NbDBCP and chromatin.NbDBCP is a negative regulator of Rx1-mediated immune responses to potato virus X(PVX),and this activity requires an intact bromodomain.Previously,Rx1 has been shown to regulate the DNA-binding activity of a Golden2-like transcription factor,NbGlk1.Rx1 and NbDBCP act synergistically to reduce NbGlk1 DNA binding,suggesting a mode of action for NbDBCP’s inhibitory effect on immunity.This study provides new mechanistic insight into the mechanism by which a chromatin-localized NLR complex co-ordinates immune signaling after pathogen perception.展开更多
Awide spectrum of Androgen insensitivity syndrome （AIS） occur due to mutations in the androgen receptor（AR）. The clinical presentation of AIS ranges from a typically male phenotype with decreased body hair and/ or...Awide spectrum of Androgen insensitivity syndrome （AIS） occur due to mutations in the androgen receptor（AR）. The clinical presentation of AIS ranges from a typically male phenotype with decreased body hair and/ or oligospermia to a typically female phenotype with primary amenorrhea and without pubic and axillary hair;展开更多
基金supported by the National Natural Science Foundation of China(Grant No.32371284)the Open Fund of the State Key Laboratory of Optoelectronic Materials and Technologies,Sun Yatsen University(Grant No.OEMT-2024-ZTS-04)support from the Physical Research Platform in the School of Physics,Sun Yatsen University(Grant No.PRPSP,SYSU).
文摘DNA imaging and visualization techniques are crucial in biological experiments and have also emerged as a powerful method for single-molecule studies.Traditional intercalating dyes(e.g.,SYTOX,EtBr,GelRed)can stain DNA but may alter its structure and mechanical properties,and cause photocleavage.Recently,a novel fluorescent DNA-binding protein(FP-DBP)was introduced,which can stain DNA without sequence preference and without inducing photocleavage.In this study,using a custom-built magnetic tweezers system,we performed DNA stretching,twisting and unzipping experiments to compare the mechanical properties of DNA with and without two kinds of intercalating dyes(SYTOX Orange and GelRed)and mCherry FP-DBP.Our results show that mCherry FP-DBP does not affect DNA structure or mechanics,unlike SYTOX Orange and GelRed,making FP-DBP a promising tool for DNA visualization in single-molecule experiments.
基金in part supported by the National Natural Science Foundation of China,Nos.30560042,81160161,81360198,and 82160255Education Department of Jiangxi Province,Nos.GJJ13198 and GJJ170021+1 种基金Jiangxi Provincial Department of Science and Technology,No.20192BAB205043Health and Family Planning Commission of Jiangxi Province,Nos.20181019 and 202210002(all to RX)。
文摘The onset of amyotrophic lateral sclerosis is usually characterized by focal death of both upper and/or lower motor neurons occurring in the motor cortex,basal ganglia,brainstem,and spinal cord,and commonly involves the muscles of the upper and/or lower extremities,and the muscles of the bulbar and/or respiratory regions.However,as the disease progresses,it affects the adjacent body regions,leading to generalized muscle weakness,occasionally along with memory,cognitive,behavioral,and language impairments;respiratory dysfunction occurs at the final stage of the disease.The disease has a complicated pathophysiology and currently,only riluzole,edaravone,and phenylbutyrate/taurursodiol are licensed to treat amyotrophic lateral sclerosis in many industrialized countries.The TAR DNA-binding protein 43 inclusions are observed in 97%of those diagnosed with amyotrophic lateral sclerosis.This review provides a preliminary overview of the potential effects of TAR DNAbinding protein 43 in the pathogenesis of amyotrophic lateral sclerosis,including the abnormalities in nucleoplasmic transport,RNA function,post-translational modification,liquid-liquid phase separation,stress granules,mitochondrial dysfunction,oxidative stress,axonal transport,protein quality control system,and non-cellular autonomous functions(e.g.,glial cell functions and prion-like propagation).
基金ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China （No.20903027）, the Natural Science Foundation of Guangdong Province of China （No.9452402301001941）, the Medical Scientific Research Foundation of Guangdong Province of China （No.B2013297）, and the University Student in Guangdong Province Innovation and Entrepreneurship Train ing Program （No.1057112019 and No.1057112013）.
文摘Theoretical studies on the electronic and geometric structures, the trend in DNA-binding affinities as well as the the structure-activity relationship （SAR） of a series of water-soluble Ru（II） methylimidazole complexes, i.e. [Ru（Mehn）4iip]^2＋ （1） （MeIm=l-methylimidazole, iip=2-（1H-imidazo-4-group）-lH-imidazo[n,5-f][1,10]phenanthroline）, [Ru（MeIm）4tip]^2＋ （2） （tip=2-（thiophene-2-group）-lH-imidazo[4,5-f] [i,10]phenanthroline）, and [Ru（Melm）42ntz]^2＋ （3） （2ntz=2-（2-nitro-l,3-thiazole-5-group）-lH-imidazo[4,5-f][1,10]phenanthroline）, were car- ried out using the density functional theory （DFT）. The electronic structures of these Ru（II） complexes were analyzed on the basis of their geometric structures optimized in aqueous solution, and the trend in the DNA-binding constants （Kb） was reasonably explained. The results show that the replacement of imidazole ligand by thiophene ligand can effectively improve the DNA-binding affinity of the complex. Meanwhile, it was found that introduc- ing the stronger electronegative N atom and NO2 group on terminal loop of intercalative ligand can obviously reduce the complex＇s LUMO and HOMO-LUMO gap energies. Based on these findings, the designed complex [Ru（MeIm）42ntz]^2＋ （3） can be expected to have the greatest Kb value in complexes 1-3. In addition, the structure-activity relationships and antitumor mechanism were also carefully discussed, and the antimetastatic activity of the designed complex 3 was predicted. Finally, the electronic absorption spectra of this series of complexes in aqueous solution were calculated, simulated and assigned using DFT/TDDFT methods as well as conductor-like polarizable continuum model （CPCM）, and were in good agreement with the experimental results.
基金Peking University Comprehensive Platform for Innovative Drug Research and Development(Grant No.2009ZX--09301--010)
文摘We have developed an on-line detection method using acridine orange as the fluorescence probe and applied this method to rapidly identify active compounds in herbal medicines. This on-line method was equipped with a high-performance liquid chromatography tandem diode array detector, electrospray ionization-ion-trap time-of-flight mass spectrometry and DNA- acridine orange fluorescence detection （HPLC-DAD-MSn-DNA-AO-FLD）. A large amount of information could be simultaneously obtained during one run, which included HPLC fingerprint, ultraviolet spectra, total ion chromatograms, MSn data of high-resolution mass spectrometry and activity profile of each compound binding with DNA. The method also provided information on structureactivity relationships and mechanism of interaction. We used this on-line method to identify five DNA-binding activity components from Lithospermum erythrorhizon sample for the first time. The result showed that the parent nucleus of shikonin derivatives could bind with DNA. The structure-activity relationship showed that the parent nucleus of shikonin derivatives plays a major role in DNA binding, not the carboxyl group on the side chain. This simple, rapid, high precision and good stability on-line method should be useful for compound separation, structural identification and screening of DNA-binding compounds in herbal medicines.
基金supported by the National Natural Science Foundation of China(Nos.60501010,60701008 and 60771024)
文摘A sensitive approach for the qualitative detection of DNA-binding protein on the microarray was developed. DNA complexes in which a partial duplex region is formed from a biotin-primer and a circle single strand DNA （ssDNA） were spotted on a microarray. The endonuclease recognition site （ERS） and the DNA-binding sites （DBS） were arranged side by side within the duplex region. The working principle of the detection system is described as follows： when the DNA-binding protein capture the DBS, the endonuclease could not attach to the ERS, and the immobilized primer in the DNA complex could be extended along the circle ssDNA by rolling circle amplification （RCA）. When no protein protects the DBS, the ERS could be attacked by the endonuclease and subsequently no rolling circle amplification occurs. Thereby we can detect the sequence specific DNA-binding activity with high-sensitivity due to the signal amplification of RCA.
文摘A new cobalt(Ⅱ) complex with tridentate ligand 2, 6-bis (benzimidazol- 2-yl)pyridine has been synthesized by microwave irradiation method and characterized by elemental analysis, electrochemical and spectral methods. The binding of the complex with calf thymus DNA has also been investigated by absorption and fluorescence spectra.
基金supported by the National Natural Science Foundation of China(No.21173197)
文摘Two silver（I）-sulfonate complexes,[Ag（NO3）（4,4＇-bipy）][Ag（HL）（4,4＇-bipy）]·2H2O（1） and[Ag（H2O）（4,4＇-bipy）][AgL（4,4＇-bipy）]·2H2O（2）,have been synthesized by in situ reaction（H2L = 2-formylbenzenesulfonic acid,4,4-bipy = 4,4-bipyridine）.1 displays two parallel 1D chains expending to a 3D supramolecule by n—n interactions and O-H…O hydrogen bonds,in which the[Ag（NO3）]or[Ag（HL）]units are joined by bridging 4,4＇-bipy molecules,respectively.The interactions between the complexes and DNA were studied by means of fluorescence spectra and surface-enhanced Raman scattering（SERS） spectra.The special configuration and intercalation effects between 1 and DNA are stronger than that between 2 and DNA.
文摘Two novel polypyridyl{PylP=2-(pyren-1-yl)-lH-imidazo[4,5-f][1,10]phenanthroline,bpy=2,2′-bipyridine,dmb=4,4′-dimethyl-2,2′-bipyridine}ruthenium(Ⅱ)complexes[Ru(bpy)_(2)(PyIP)]^(2+)(1)and[Ru(dmb)_(2)(PyIP)]^(2+)(2)have been synthesized and characterized by elemental analysis,ES-MS and a H NMR spectroscopy.The DNA-binding of these complexes were investigated by spectroscopic methods and viscosity measurements.The experimental results indicate that both complexes 1 and 2 bind to calf thymus DNA in classical intercalation mode,and however,complex 1 intercalated more strongly than complex 2,due to the different ancillary ligands.
基金supported by the Natural Science Project of Zhejiang Province(LY12B01003)
文摘A complex [Cd2Na2（BOABA）2（H2O）8]·H2O（1） was synthesized by using 2,4-bisoxyacetate-benzoic acid（H3BOABA） and Cd（OH）2. It was characterized by elemental analysis, IR spectra, and single-crystal X-ray diffraction. Complex 1 shows a two-dimensional 3-connected rigid plane. The interactions between the ligand and its complex with DNA were studied by Et Br fluorescence probe. Photoluminescent studies indicate that the complex may be excellent candidates for potential photoactive materials.
基金This work was supported by grants 2018YFE0202300,2018YFA0704002 from the National Key R&D Program of Chinagrant 21735007 from the National Natural Science Foundation of China to M.L.grant 21991083 from the National Natural Science Foundation of China to Y.H.
文摘The WRKY proteins are a family of plant-specific transcription factors(TFs)that are widely involved in plant development and anti-stress responses.Arabidopsis WRKY11(AtWRKY11)functions in regulating plant defense against abiotic stress and belongs to the Ild subgroup of WRKY TFs.We herein report the expres sion,purification and preliminary structural characterization of AtWRKY11 DNA-binding domain(DBD)using solution NMR Almost complete backbone chemical shift assignments of AtWRKY11-DBD have been ob-tained.Chemical shift-based secondary structure analysis suggests that AtWRKY11-DBD may exhibit local conformational diferences from the X-ray structure of the C-terminal WRKY domain of AtWRKY1,particularly in the β1 and β5 strands.Our current study provides the basis for further structural and interactional studies.
基金supported by the National Natural Foundation of China(81672007 and 81971920 to Wenran Zhao,81871652 to Zhaohua Zhong,and 81772188 to Yan Wang)Health and Family Planning Commission of Heilongjiang Province(2017-158 to Xiaoman Wo)
文摘Enterovirus A71(EV-A71)is one of the etiological pathogens leading to hand,foot,and mouth disease(HFMD),which can cause severe neurological complications.The neuropathogenesis of EV-A71 infection is not well understood.The mislocalization and aggregation of TAR DNA-binding protein 43(TDP-43)is the pathological hallmark of amyotrophic lateral sclerosis(ALS).However,whether TDP-43 was impacted by EV-A71 infection is unknown.This study demonstrated that TDP-43 was cleaved during EV-A71 infection.The cleavage of TDP-43 requires EV-A71 replication rather than the activated caspases due to viral infection.TDP-43 is cleaved by viral protease 3 C between the residues 331 Q and332 S,while mutated TDP-43(Q331 A)was not cleaved.In addition,mutated 3 C which lacks the protease activity failed to induce TDP-43 cleavage.We also found that TDP-43 was translocated from the nucleus to the cytoplasm,and the mislocalization of TDP-43 was induced by viral protease 2 A rather than 3 C.Taken together,we demonstrated that TDP-43 was cleaved by viral protease and translocated to the cytoplasm during EV-A71 infection,implicating the possible involvement of TDP-43 in the pathogenesis of EV-A71 infection.
基金supported by the Natural Science Foundation of Zhejiang Province(LY12B01003)
文摘A bismuth（Ⅲ） complex 1 （H2-4,4＇-bipy）[Bi（HPPA）5]（H2PPA）.4H2O （H2PPA = p- hydroxy- phenylacetic acid, 4,4＇-bipy = 4,4＂-bipyridyl） was hydrothermally synthesized from p-hydroxy-phenylacetic acid （H2PPA）, Bi（NO3）3＂6H20 and 4,4＇-bipyridyl, and characterized by elemental analysis, IR, molar conductivity and TG. The single-crystal X-ray diffraction studies demonstrated that the complex is of monoclinic system, space group P21 with a = 10.928（7）, b = 22.558（7）, c = 11.313（7） A, β = 91.864（4）°, V = 2787.7（4） A3, Z = 2, C58H61BiN2O22, Mr = 1347.07, F（000） = 1364, Dc= 1.605 g/cm-3, p（MoKa） = 3.247 mm-1, the final R = 0.0269 and wR = 0.0540 for 9776 observed reflections with I 〉 2or（I）. The bismuth（I/I） is seven-coordinated with O atoms, forming a monocapped octahedral geometry. Complex 1 further forms a 3D supramolecular architecture by hydrogen bonds and π-π stacking interactions. Moreover, the interaction between the complex and DNA was studied by EtBr fluoescent probe.
文摘GATA-6 mRNA utilizes two Met-codons in frame as translational initiation codons in cultured mammalian cells. Deletion of the nucleotide sequence encoding the PEST sequence between the two initiation codons unusually reduced the protein molecular size on SDS-polyacrylamide gel-electrophoresis. The reduced molecular size is ascribed to the molecular property of GATA-6, since both amino-and carboxy-lterminal tags introduced into GATA-6 were detected on the gel. This PEST sequence seems to contribute to expansion of the long-type GATA-6 molecule. The long-type GATA-6 containing the PEST sequence exhibits more activation potential than that without this sequence, the latter’s activity being similar to that of the short-type GATA-6. We further demonstrated that human colon and lung cancer cell lines express both the long-type GATA-6 and the short-type GATA-6 in their nuclei.
文摘Transcription factor SPI is a protcin present in mammalian cells that binds to GC box promoter clements of Gene and selectively activates mRNA synthesis. The gene contains functional recognition sites. It contains three continuous zinc finger motifs, which are believed being mctalloprotein structures that interact with DNA. We synthesized the second zine finger fragment of SP1 (SP1-ZF2) and its mutant (SP1-ZF2 / HT. E20→H. R23→T), we also synthesized the Cys-Cys loop (ZF6) and the His-His loop (ZF5) of SPI and linked the twoloops together using a β-turn structure to obtain a finger mimic analogue (ZF-15) by stepwise solid-phase technique. Atomic absorption studies show that SP 1-ZF2 and SP1-ZF2 / HT bind zinc cquimolarly, but ZF-15 docs not bind Zn anyway. The CD experiments demonstrate a significant change in secondary structure in the prescnce or absence of Zn to SP1-ZF2 and SP1-ZF2/ HT, but there is no change about ZF-15. Gcl-retardation clectrophoresis assays indicate that SP1-ZF2 binds to DNA sequence specifically in the presence of Zn, but SP1-ZF2 / HT docs not bind as SP 1-ZF2 did. We observed that a single zine finger like SP1-ZF2 is able to bind DNA sequence specifically.
文摘Three mononuclear oxovanadium complexes [VO(Hbid)(CF3PIP)] (1) (Hbid=(E)-2-(2-hydroxybenzylideneamino) isoindoline-1,3-dione, CF3PIP=2-(2-trifluoromethyl phenyl)imidazole[4,5-f][1,10] phenanthroline), [VO(Hbid)(m-CF3PIP)];(2) (m-CF3PIP=2-(3-trifluoromethyl phenyl)imidazole [4, 5-f][1,10]phenanthroline) and [VO(Hbid)(p-CF3PIP)];(3) (p-CF3PIP=2-(4-trifluoromethyl phenyl) imidazole[4,5-f][1,10]phenanthroline) have been synthesized and characterized by elemental analysis, IR, molar conductance, ES-MS and 1H NMR. The DNA-binding properties of these complexes were studied by using UV-Vis absorption titration, fluorescence spectra, viscosity measurements and thermal denaturation studies. The results show that 1, 2 and 3 interact with calf thymus DNA (CT-DNA) by intercalation modes and the magnitude of their intrinsic binding constants (Kb values) follows the order: 2 < 1 < 3. Furthermore, their photocleavage properties with pBR322 plasmid DNA were investigated by agarose gel electrophoresis experiments. The DNA cleavage capacity of complex 3 is also stronger than that of 1 and 2.
基金This work was supported by The National Natural Science Foundation of China grants(31530085,31900609,31900207,32000183)The National Key Research and Development Program of China grant(2017YFA0503802)The Science and Technology Commission of Shanghai Municipality grant(18DZ2260500)。
文摘Cryptochromes are blue light photoreceptors that mediate various light responses in plants and mammals. The heterotrimeric G-protein is known to regulate various physiological processes in plants and mammals. In Arabidopsis, cryptochrome 1(CRY1) and the G-protein β subunit AGB1 act antagonistically to regulate stomatal development.The molecular mechanism by which CRY1 and AGB1 regulate this process remains unknown.Here, we show that Arabidopsis CRY1 acts partially through AGB1, and AGB1 acts through SPEECHLESS(SPCH), a master transcription factor that drives stomatal initiation and proliferation, to regulate stomatal development. We demonstrate that AGB1 physically interacts with SPCH to block the b HLH DNA-binding domain of SPCH and inhibit its DNA-binding activity. Moreover, we demonstrate that photoexcited CRY1 represses the interaction of AGB1 with SPCH to release AGB1 inhibition of SPCH DNA-binding activity, leading to the expression of SPCH-target genes promoting stomatal development. Taken together, our results suggest that the mechanism by which CRY1 promotes stomatal development involves positive regulation of the DNA-binding activity of SPCH mediated by CRY1 inhibition of the AGB1-SPCH interaction. We propose that the antagonistic regulation of SPCH DNA-binding activity by CRY1 and AGB1 may allow plants to balance light and G-protein signaling and optimize stomatal density and pattern.
基金supported by Biotechnology and Biological Sciences Research Council grant BB/M007405/1(to M.J.C.and L.-O.P.)the Dutch Technology Foundation STW and Earth and Life Sciences ALW(to E.J.S.,O.C.A.S.,and A.G.)VICI project no.865.14.003(to F.L.W.T.)(Netherlands Organization for Scientific Research).
文摘Plant NLR proteins enable the immune systemto recognize and respond to pathogen attack.An early consequence of immune activation is transcriptional reprogramming.SomeNLRs have been shownto act in the nucleus and interact with transcription factors.The Rx1 NLR protein of potato binds and distorts doublestranded DNA.However,the components of the chromatin-localized Rx1 complex are largely unknown.Here,we report a physical and functional interaction between Rx1 and NbDBCP,a bromodomaincontaining chromatin-interacting protein.NbDBCP accumulates in the nucleoplasmand nucleolus,interacts with chromatin,and redistributes Rx1 tothe nucleolus in a subpopulation of imaged cells.Rx1 overexpression reduces the interaction between NbDBCP and chromatin.NbDBCP is a negative regulator of Rx1-mediated immune responses to potato virus X(PVX),and this activity requires an intact bromodomain.Previously,Rx1 has been shown to regulate the DNA-binding activity of a Golden2-like transcription factor,NbGlk1.Rx1 and NbDBCP act synergistically to reduce NbGlk1 DNA binding,suggesting a mode of action for NbDBCP’s inhibitory effect on immunity.This study provides new mechanistic insight into the mechanism by which a chromatin-localized NLR complex co-ordinates immune signaling after pathogen perception.
文摘Awide spectrum of Androgen insensitivity syndrome （AIS） occur due to mutations in the androgen receptor（AR）. The clinical presentation of AIS ranges from a typically male phenotype with decreased body hair and/ or oligospermia to a typically female phenotype with primary amenorrhea and without pubic and axillary hair;
