G-quadruplex DNA(G4)can function as a kind of nucleic acid apoenzyme for constructing G4/hemin biocatalyst to mimic the catalytic function of hemoprotein.However,achieving stereoselective control with G4/hemin remains...G-quadruplex DNA(G4)can function as a kind of nucleic acid apoenzyme for constructing G4/hemin biocatalyst to mimic the catalytic function of hemoprotein.However,achieving stereoselective control with G4/hemin remains a persistent challenge.Here,we report that a PW17/hemin(PW17:5’-GGGTAGGGCGGGTTGGG-3’),adopting the 5’-5’stacked dimeric parallel G4 topology,can realize the enantioselective induction in intramolecular cyclopropanation of allyl diazoacetates with enantioselectivity up to 87%ee.Spectroscopic characterization and catalytic results demonstrate that the relatively open G-quartet of the 3’terminal in dimeric PW17 contributes a catalytic pocket for hemin accommodation and plays a pivotal role in enantioselective control.This finding expands the unique repertoire of heme enzyme using biological scaffolds from proteins to nucleic acids and resolves the long-standing challenge of stereochemical control in G4/hemin catalysis.展开更多
G-quadruplexes(GQs) are guanine-rich, non-canonical nucleic acid structures that play fundamental roles in biological processes. Their structure and function are strongly influenced by their hydration shells. Although...G-quadruplexes(GQs) are guanine-rich, non-canonical nucleic acid structures that play fundamental roles in biological processes. Their structure and function are strongly influenced by their hydration shells. Although extensively studied through various experimental and computational methods, hydration patterns near DNA remain under debate due to the chemically and topologically heterogeneous nature of the exposed surface. In this work, we employed all-atom molecular dynamics(MD) simulation to study the hydration patterns of GQ DNA. The Drude oscillator model was used in MD simulation as a computationally efficient method for modeling electronic polarization in DNA ion solutions. Hydration structure was analyzed in terms of radial distribution functions and high-density three-dimensional hydration sites. Analysis of hydration dynamics focused on self-diffusion rates and orientation time correlation at different structural regions of GQ DNA.The results show highly heterogeneous hydration patterns in both structure and dynamics;for example, there are several insular high-density sites in the inner channel, and ‘spine of water’ in the groove. For water inside the loop, anomalous diffusion is present over a long time scale, but for water around the phosphate group and groove, diffusion becomes normal after ~30 ps. These essentially correspond to deeply buried structural water and strong interaction with DNA, respectively.展开更多
In this study, one mononuclear zinc（II） complex with 1,2-bis CAP （（5-chlorosalicylidene amino）-phenylene）： C22C13N2035Znl5 H0125 （Zn-CAP） was synthesized. The binding properties of Zn-CAP with G-quadruplex DN...In this study, one mononuclear zinc（II） complex with 1,2-bis CAP （（5-chlorosalicylidene amino）-phenylene）： C22C13N2035Znl5 H0125 （Zn-CAP） was synthesized. The binding properties of Zn-CAP with G-quadruplex DNA and ctDNA （calf thymus DNA） were examined by fluorescence, CD （circular dichroism） spectroscopic and FRET （fluorescence resonance energy transfer） assay. In the fluorescence emission spectral analysis, the addition of three series of G-quadruplex DNA （G4-HTG21, G4-Pu27 and G4-c-kit-l） into the Zn-CAP solution induced moderate or add hypochromicity with total quenching ratios of 10.73%, 15.07% and 8.59% in the presence of K＋ were achieved, respectively. While the addition of ctDNA under same condition only caused 7.08% quenching on the fluorescence emission of Zn-CAP. In the CD spectral analysis, the interaction with Zn-CAP could induce significant spectral changes on the CD absorption of G4-HTG21, G4-Pu27 and G4-c-kit-1, with 106.00%, 93.06%, 113.47% increment at 232 nm absorption, along with a 81.11%, 92.80%, 83.72% decrement at 295 nm or 270 nm absorption, which demonstrated that the antiparallel structure of G-quadruplex DNA is more stable in the presence of Zn-CAP. Comparatively, the addition of Zn-CAP could induce significant spectral changes on the CD absorption of double helix ctDNA, with 64.17% decrement on the positive peak absorption, along with a 90.91% increment on the negative peak absorption. On the other hand, in the FRET-melting assay analysis, it was clear that Zn-CAP at 0.5 equivalences could raise the melting temperature of G-quadruplex （F2 IT or FPul 8T） by 3.45℃ and 15.85℃, indicating an obvious stabilization effect of Zn-CAP on G-quadruplex in Pu27. All the results indicated that Zn-CAP exhibited higher binding affinity and binding intensity to G-quadruplex DNA than ctDNA, especially G-quadruplex Pu27.展开更多
G-quadruplexes(GQs) are guanine-rich, non-canonical nucleic acid structures that play fundamental roles in biological processes. The topology of GQs is associated with the sequences and lengths of DNA, the types of li...G-quadruplexes(GQs) are guanine-rich, non-canonical nucleic acid structures that play fundamental roles in biological processes. The topology of GQs is associated with the sequences and lengths of DNA, the types of linking loops, and the associated metal cations. However, our understanding on the basic physical properties of the formation process and the stability of GQs is rather limited. In this work, we employed ab initio, molecular dynamics(MD), and steered MD(SMD)simulations to study the interaction between loop bases and ions, and the effect on the stability of G-quadruplex DNA, the Drude oscillator model was used in MD and SMD simulations as a computationally efficient manner method for modeling electronic polarization in DNA ion solutions. We observed that the binding energy between DNA bases and ions(K^(+)/Na^(+))is about the base stacking free energies indicates that there will be a competition among the binding of M^(+)-base, H-bonds between bases, and the base-stacking while ions were bound in loop of GQs. Our SMD simulations indicated that the side loop inclined to form the base stacking while the loop sequence was Thy or Ade, and the cross-link loop upon the G-tetrads was not easy to form the base stacking. The base stacking side loop complex K+was found to have a good stabilization synergy. Although a stronger interaction was observed to exist between Cyt and K+, such an interaction was unable to promote the stability of the loop with the sequence Cyt.展开更多
Since the discovery of left-handed G-quadruplex(L-G4)structure formed by natural DNA,there has been a growing interest in its potential functions.This study utilised it to catalyse enantioselective Diels-Alder reactio...Since the discovery of left-handed G-quadruplex(L-G4)structure formed by natural DNA,there has been a growing interest in its potential functions.This study utilised it to catalyse enantioselective Diels-Alder reactions,considering its different optical rotation compared to an ordinary G4.It was determined that when L-G4 was used with a combination of copper(Ⅱ)ions,there was a good enantioselectivity(-52%ee)without further addition of ligands.When further consideration was given by adding G4 ligands,G4 was further stabilised,even obtaining a better enantioselectivity(up to-80%ee).Moreover,when using ligands that have regulatory effects on G4,the ee value can be adjusted.In this work,a minimal left-handed G4 was reported.A follow-up study was also con ducted,which recovers that the minimal left-handed G4 remains its catalytic effect and enantioselectivity,but is not so effective as the former case.This indicates that a complete G4 structure is relatively conducive to chiral catalysis.展开更多
The hypoxic tumor microenvironment severely limits the effectiveness of photodynamic therapy(PDT)in hepatocellular carcinoma(HCC).To overcome this limitation,we designed and synthesized a dual-functional photosensitiz...The hypoxic tumor microenvironment severely limits the effectiveness of photodynamic therapy(PDT)in hepatocellular carcinoma(HCC).To overcome this limitation,we designed and synthesized a dual-functional photosensitizer,PorRu,by conjugating a porphyrin unit with a ruthenium(II)polypyridyl complex through a flexible alkyl chain.PorRu is engineered to achieve specific accumulation in HCC cells and“dual-lock”binding with G-quadruplex DNA(G4 DNA).It demonstrated approximately 3-6 folds higher photocytotoxicity against HCC cells compared to its individual components,owing to enhanced tumor targeting and improved Type I photochemical reactivity.Unlike conventional oxygen-dependent PDT,PorRu efficiently generates reactive oxygen species(ROS)under near-infrared irradiation,directly oxidizing guanine bases in G4 DNA and causing extensive oxidative damage under both normoxic and hypoxic conditions.The ROS burst induces severe oxidative stress,mitochondrial dysfunction,and the release of mitochondrial DNA(mtDNA),ultimately activating the inflammasome and triggering pyroptosis.In vivo studies validated the potent tumor-suppressive capability of PorRu,highlighting its potential to circumvent hypoxia-induced therapy resistance.This work not only presents PorRu as a promising agent for precise HCC targeting but also offers a novel strategy to enhance PDT efficacy against hypoxic tumors.展开更多
目的运用meta分析方法系统评价补肾方剂治疗男性不育症患者精子DNA损伤(SDF)的有效性和安全性。方法从中国知网、维普、万方、PubMed、Cochrane Library、Embase、Web of Science数据库中检索补肾方剂改善SDF的随机对照试验(RCT)研究,...目的运用meta分析方法系统评价补肾方剂治疗男性不育症患者精子DNA损伤(SDF)的有效性和安全性。方法从中国知网、维普、万方、PubMed、Cochrane Library、Embase、Web of Science数据库中检索补肾方剂改善SDF的随机对照试验(RCT)研究,对文献进行方法学质量评价,运用RevMan5.3.5软件进行meta分析,并对结局指标进行GRADE质量分级。结果共纳入17项RCT研究,涉及2164例男性患者。与西医常规治疗相比,补肾方剂能够显著改善男性不育症患者DNA碎片指数(DFI)(MD=-6.50,95%CI:-7.88~-5.11,P<0.01),提高配偶妊娠率(RR=2.11,95%CI:1.12~4.00,P=0.87)、精子总活率(MD=5.56,95%CI:4.39~6.74,P<0.01)、前向运动精子百分率(MD=6.82,95%CI:5.62~8.03,P<0.01)、精子浓度(MD=6.51,95%CI:3.81~9.21,P<0.01)和正常形态精子百分率(MD=1.26,95%CI:0.45~2.06,P<0.01),且补肾方剂不会增加不良反应的发生。结论低到中等质量证据表明,与西医常规治疗相比,补肾方剂在改善男性不育症患者DFI、精液参数、配偶妊娠率等方面具有一定优势,且安全性较好。展开更多
文摘G-quadruplex DNA(G4)can function as a kind of nucleic acid apoenzyme for constructing G4/hemin biocatalyst to mimic the catalytic function of hemoprotein.However,achieving stereoselective control with G4/hemin remains a persistent challenge.Here,we report that a PW17/hemin(PW17:5’-GGGTAGGGCGGGTTGGG-3’),adopting the 5’-5’stacked dimeric parallel G4 topology,can realize the enantioselective induction in intramolecular cyclopropanation of allyl diazoacetates with enantioselectivity up to 87%ee.Spectroscopic characterization and catalytic results demonstrate that the relatively open G-quartet of the 3’terminal in dimeric PW17 contributes a catalytic pocket for hemin accommodation and plays a pivotal role in enantioselective control.This finding expands the unique repertoire of heme enzyme using biological scaffolds from proteins to nucleic acids and resolves the long-standing challenge of stereochemical control in G4/hemin catalysis.
基金supported by the National Natural Science Foundation of China (Grant Nos. 11705160 and 11647074)。
文摘G-quadruplexes(GQs) are guanine-rich, non-canonical nucleic acid structures that play fundamental roles in biological processes. Their structure and function are strongly influenced by their hydration shells. Although extensively studied through various experimental and computational methods, hydration patterns near DNA remain under debate due to the chemically and topologically heterogeneous nature of the exposed surface. In this work, we employed all-atom molecular dynamics(MD) simulation to study the hydration patterns of GQ DNA. The Drude oscillator model was used in MD simulation as a computationally efficient method for modeling electronic polarization in DNA ion solutions. Hydration structure was analyzed in terms of radial distribution functions and high-density three-dimensional hydration sites. Analysis of hydration dynamics focused on self-diffusion rates and orientation time correlation at different structural regions of GQ DNA.The results show highly heterogeneous hydration patterns in both structure and dynamics;for example, there are several insular high-density sites in the inner channel, and ‘spine of water’ in the groove. For water inside the loop, anomalous diffusion is present over a long time scale, but for water around the phosphate group and groove, diffusion becomes normal after ~30 ps. These essentially correspond to deeply buried structural water and strong interaction with DNA, respectively.
文摘In this study, one mononuclear zinc（II） complex with 1,2-bis CAP （（5-chlorosalicylidene amino）-phenylene）： C22C13N2035Znl5 H0125 （Zn-CAP） was synthesized. The binding properties of Zn-CAP with G-quadruplex DNA and ctDNA （calf thymus DNA） were examined by fluorescence, CD （circular dichroism） spectroscopic and FRET （fluorescence resonance energy transfer） assay. In the fluorescence emission spectral analysis, the addition of three series of G-quadruplex DNA （G4-HTG21, G4-Pu27 and G4-c-kit-l） into the Zn-CAP solution induced moderate or add hypochromicity with total quenching ratios of 10.73%, 15.07% and 8.59% in the presence of K＋ were achieved, respectively. While the addition of ctDNA under same condition only caused 7.08% quenching on the fluorescence emission of Zn-CAP. In the CD spectral analysis, the interaction with Zn-CAP could induce significant spectral changes on the CD absorption of G4-HTG21, G4-Pu27 and G4-c-kit-1, with 106.00%, 93.06%, 113.47% increment at 232 nm absorption, along with a 81.11%, 92.80%, 83.72% decrement at 295 nm or 270 nm absorption, which demonstrated that the antiparallel structure of G-quadruplex DNA is more stable in the presence of Zn-CAP. Comparatively, the addition of Zn-CAP could induce significant spectral changes on the CD absorption of double helix ctDNA, with 64.17% decrement on the positive peak absorption, along with a 90.91% increment on the negative peak absorption. On the other hand, in the FRET-melting assay analysis, it was clear that Zn-CAP at 0.5 equivalences could raise the melting temperature of G-quadruplex （F2 IT or FPul 8T） by 3.45℃ and 15.85℃, indicating an obvious stabilization effect of Zn-CAP on G-quadruplex in Pu27. All the results indicated that Zn-CAP exhibited higher binding affinity and binding intensity to G-quadruplex DNA than ctDNA, especially G-quadruplex Pu27.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11705160 and 11647074)。
文摘G-quadruplexes(GQs) are guanine-rich, non-canonical nucleic acid structures that play fundamental roles in biological processes. The topology of GQs is associated with the sequences and lengths of DNA, the types of linking loops, and the associated metal cations. However, our understanding on the basic physical properties of the formation process and the stability of GQs is rather limited. In this work, we employed ab initio, molecular dynamics(MD), and steered MD(SMD)simulations to study the interaction between loop bases and ions, and the effect on the stability of G-quadruplex DNA, the Drude oscillator model was used in MD and SMD simulations as a computationally efficient manner method for modeling electronic polarization in DNA ion solutions. We observed that the binding energy between DNA bases and ions(K^(+)/Na^(+))is about the base stacking free energies indicates that there will be a competition among the binding of M^(+)-base, H-bonds between bases, and the base-stacking while ions were bound in loop of GQs. Our SMD simulations indicated that the side loop inclined to form the base stacking while the loop sequence was Thy or Ade, and the cross-link loop upon the G-tetrads was not easy to form the base stacking. The base stacking side loop complex K+was found to have a good stabilization synergy. Although a stronger interaction was observed to exist between Cyt and K+, such an interaction was unable to promote the stability of the loop with the sequence Cyt.
基金This work was supported by the National Natural Science Foundation of China(Nos.21432008,91753201,and 21721005).
文摘Since the discovery of left-handed G-quadruplex(L-G4)structure formed by natural DNA,there has been a growing interest in its potential functions.This study utilised it to catalyse enantioselective Diels-Alder reactions,considering its different optical rotation compared to an ordinary G4.It was determined that when L-G4 was used with a combination of copper(Ⅱ)ions,there was a good enantioselectivity(-52%ee)without further addition of ligands.When further consideration was given by adding G4 ligands,G4 was further stabilised,even obtaining a better enantioselectivity(up to-80%ee).Moreover,when using ligands that have regulatory effects on G4,the ee value can be adjusted.In this work,a minimal left-handed G4 was reported.A follow-up study was also con ducted,which recovers that the minimal left-handed G4 remains its catalytic effect and enantioselectivity,but is not so effective as the former case.This indicates that a complete G4 structure is relatively conducive to chiral catalysis.
基金supported by the National Natural Science Foundation of China(81572926,81703349)the China Postdoctoral Science Foundation(2017M610576)the Natural Science Foundation of Guangdong Province(2024A1515013282).
文摘The hypoxic tumor microenvironment severely limits the effectiveness of photodynamic therapy(PDT)in hepatocellular carcinoma(HCC).To overcome this limitation,we designed and synthesized a dual-functional photosensitizer,PorRu,by conjugating a porphyrin unit with a ruthenium(II)polypyridyl complex through a flexible alkyl chain.PorRu is engineered to achieve specific accumulation in HCC cells and“dual-lock”binding with G-quadruplex DNA(G4 DNA).It demonstrated approximately 3-6 folds higher photocytotoxicity against HCC cells compared to its individual components,owing to enhanced tumor targeting and improved Type I photochemical reactivity.Unlike conventional oxygen-dependent PDT,PorRu efficiently generates reactive oxygen species(ROS)under near-infrared irradiation,directly oxidizing guanine bases in G4 DNA and causing extensive oxidative damage under both normoxic and hypoxic conditions.The ROS burst induces severe oxidative stress,mitochondrial dysfunction,and the release of mitochondrial DNA(mtDNA),ultimately activating the inflammasome and triggering pyroptosis.In vivo studies validated the potent tumor-suppressive capability of PorRu,highlighting its potential to circumvent hypoxia-induced therapy resistance.This work not only presents PorRu as a promising agent for precise HCC targeting but also offers a novel strategy to enhance PDT efficacy against hypoxic tumors.
文摘目的运用meta分析方法系统评价补肾方剂治疗男性不育症患者精子DNA损伤(SDF)的有效性和安全性。方法从中国知网、维普、万方、PubMed、Cochrane Library、Embase、Web of Science数据库中检索补肾方剂改善SDF的随机对照试验(RCT)研究,对文献进行方法学质量评价,运用RevMan5.3.5软件进行meta分析,并对结局指标进行GRADE质量分级。结果共纳入17项RCT研究,涉及2164例男性患者。与西医常规治疗相比,补肾方剂能够显著改善男性不育症患者DNA碎片指数(DFI)(MD=-6.50,95%CI:-7.88~-5.11,P<0.01),提高配偶妊娠率(RR=2.11,95%CI:1.12~4.00,P=0.87)、精子总活率(MD=5.56,95%CI:4.39~6.74,P<0.01)、前向运动精子百分率(MD=6.82,95%CI:5.62~8.03,P<0.01)、精子浓度(MD=6.51,95%CI:3.81~9.21,P<0.01)和正常形态精子百分率(MD=1.26,95%CI:0.45~2.06,P<0.01),且补肾方剂不会增加不良反应的发生。结论低到中等质量证据表明,与西医常规治疗相比,补肾方剂在改善男性不育症患者DFI、精液参数、配偶妊娠率等方面具有一定优势,且安全性较好。
