Pyridine-based ligands functionalized with one(PyHis)or two histidine(PydiHis)moieties were synthesized,and their copper_((II))complexes were studied as novel antioxidant systems.The complexes were characterized by pH...Pyridine-based ligands functionalized with one(PyHis)or two histidine(PydiHis)moieties were synthesized,and their copper_((II))complexes were studied as novel antioxidant systems.The complexes were characterized by pH-potentiometric,spectroscopic(UV-vis,circular dichroism,continuous-wave and pulsed electron paramagnetic spectroscopy(EPR)),computational(DFT)and X-ray diffraction methods.The complexes show high thermodynamic stability.The PyHis complex possesses a(COO^(-),N^(py),N^(-),N_(Im))donor set,while PydiHis binds copper_((II))via a(N_(Im),N_(py),N^(-),N_(Im))donor set at physiological pH.The PyHis and PydiHis complexes of copper_((II))exhibit negligible(IC_(50)=147±15μM)and outstanding(IC_(50)=0.64±0.07μM)superoxide dismutase(SOD)activity,respectively.The noted difference is attributed to the structural flexibility of the latter complex as confirmed by pulsed EPR spectroscopy.The antioxidant activity of the copper_((II))complexes was also tested in vivo by monitoring their effects on the mycelial growth of Aspergillus niger under oxidative stress.Both complexes were able to protect the cells under these conditions;however,the copper_((II))complex of PydiHis was more effective in accordance with its excellent SOD activity.Consequently,the copper_((II))complex of PydiHis stands out as an efficient,low-molecularweight SOD mimic combining high catalytic activity with proven biological efficacy under oxidative stress conditions,making it a promising candidate for medical applications.展开更多
Multidisciplinary protein design is reported on a novel metallopeptide mimicking the binding loop of nickel containing SOD enzyme(NiSOD).D-Penicillamine,a natural decomposition product of penicillin,was introduced int...Multidisciplinary protein design is reported on a novel metallopeptide mimicking the binding loop of nickel containing SOD enzyme(NiSOD).D-Penicillamine,a natural decomposition product of penicillin,was introduced into the peptide chain yielding the H(Pen)DLPCGLY(wtPen)peptide.The nickel(Ⅱ)binding ability of wtPen was characterized by thermodynamic(pH-potentiometry),spectroscopic(UV-Vis,CD,MS,NMR)and computational techniques(full DFT and Molecular Dynamics methods).Oxidation of the Ni(Ⅱ)complex by KO_(2)yields a square pyramidal Ni(Ⅲ)species coordinated by the axial His-N in a welldefinedα-helix folding state.The structure of the Ni(Ⅲ)species was analyzed by EPR spectroscopy and theoretical methods confirming that the donor set involved in the metal ion coordination and the folding state are retained after oxidation.The complex exhibits superior SOD activity which was studied by sequential stopped-flow method.Thorough analysis of the data shows that the Ni(Ⅲ)species rapidly accumulates in the nickel catalyzed decomposition of superoxide anion.Accordingly,the presence of the penicillamine moiety close to the catalytic center increases the life-time of the Ni(Ⅲ)transient species.In contrast,Ni(Ⅲ)exists only at relatively low concentration level in the dismutation reaction catalyzed by the native NiSOD enzyme fragment.展开更多
^(64)Cu is considered to be one of the most promising radioisotopes in radiotheranostics (combining therapeutics with diagnostics) because its positron emission is suitable for PET imaging while the combination of its...^(64)Cu is considered to be one of the most promising radioisotopes in radiotheranostics (combining therapeutics with diagnostics) because its positron emission is suitable for PET imaging while the combination of its β^(-) and Auger electrons delivers a therapeutic effect. In this work, we present a thorough coordination chemical characterization of two Cu(Ⅱ) complexes formed from the cross-bridged pentaazamacrocyclic CB-15aneN_(5) and its bifunctional derivative. The Cu(Ⅱ) chelates possess high thermodynamic stability, fast complexation and moderate inertness under harsh conditions (t_(1/2)=2.3 h, 5 M HCl, 50℃). EPR measurements and DFT calculations were carried out for characterizing their structure in solution. Furthermore, the radiolabeling experiments performed with ^(61)Cu(Ⅱ) confirmed the fast complexation even in the µM concentration range at pH=6.0. On the basis of these results, the CB-15aneN_(5) ligand family serves as an excellent platform for Cu(Ⅱ) complexation in radiotheranostics.展开更多
基金support of the Hungarian National Research,Development and Innovation Office(OTKA K-139140(I.F.),K-146406(L.K.)and K-138489(E.F.))support of the János Bolyai Research Scholarship of the Hungarian Academy of Sciences and the 2021-4.1.2-NEMZ_KI-2024-00042 project+1 种基金supported by the EKÖP-24-3 University Research Scholarship Program of the Ministry for Culture and Innovation from the source of the National Research,Development and Innovation Fund and the University of Debrecen Scientific Research Bridging Fund(DETKA)Scientific Research Flanders(FWO-Vlaanderen)for infrastructure funding for the EPR instrumentation(No.I004920N).
文摘Pyridine-based ligands functionalized with one(PyHis)or two histidine(PydiHis)moieties were synthesized,and their copper_((II))complexes were studied as novel antioxidant systems.The complexes were characterized by pH-potentiometric,spectroscopic(UV-vis,circular dichroism,continuous-wave and pulsed electron paramagnetic spectroscopy(EPR)),computational(DFT)and X-ray diffraction methods.The complexes show high thermodynamic stability.The PyHis complex possesses a(COO^(-),N^(py),N^(-),N_(Im))donor set,while PydiHis binds copper_((II))via a(N_(Im),N_(py),N^(-),N_(Im))donor set at physiological pH.The PyHis and PydiHis complexes of copper_((II))exhibit negligible(IC_(50)=147±15μM)and outstanding(IC_(50)=0.64±0.07μM)superoxide dismutase(SOD)activity,respectively.The noted difference is attributed to the structural flexibility of the latter complex as confirmed by pulsed EPR spectroscopy.The antioxidant activity of the copper_((II))complexes was also tested in vivo by monitoring their effects on the mycelial growth of Aspergillus niger under oxidative stress.Both complexes were able to protect the cells under these conditions;however,the copper_((II))complex of PydiHis was more effective in accordance with its excellent SOD activity.Consequently,the copper_((II))complex of PydiHis stands out as an efficient,low-molecularweight SOD mimic combining high catalytic activity with proven biological efficacy under oxidative stress conditions,making it a promising candidate for medical applications.
基金the financial support of the Hungarian National Research,Development and Innovation Office(NKFIH PD-128326 and K-124983)The research was also financed by the EU and co-financed by the European Regional Development Fund(under the projects GINOP-2.3.2-15-2016-00008).E.G.and G.S.thank Regione Autonoma della Sardegna(grant RASSR79857)+1 种基金Fondazione di Sardegna(FdS2017Garribba)for financial support.G.S.also thank Spanish MICINN’Juan de la Cierva program,FJC2019-039135-Isupported by theÚNKP-21-4-II New National Excellence Program of the Ministry for Innovation and Technology from the source of the National,Research,Development and Innovation Fund and prepared with the professional support of the Doctoral Student Scholarship Program of the Co-operative Doctoral Program of the Ministry of Innovation and Technology financed from the National Research,Development and Innovation Office.
文摘Multidisciplinary protein design is reported on a novel metallopeptide mimicking the binding loop of nickel containing SOD enzyme(NiSOD).D-Penicillamine,a natural decomposition product of penicillin,was introduced into the peptide chain yielding the H(Pen)DLPCGLY(wtPen)peptide.The nickel(Ⅱ)binding ability of wtPen was characterized by thermodynamic(pH-potentiometry),spectroscopic(UV-Vis,CD,MS,NMR)and computational techniques(full DFT and Molecular Dynamics methods).Oxidation of the Ni(Ⅱ)complex by KO_(2)yields a square pyramidal Ni(Ⅲ)species coordinated by the axial His-N in a welldefinedα-helix folding state.The structure of the Ni(Ⅲ)species was analyzed by EPR spectroscopy and theoretical methods confirming that the donor set involved in the metal ion coordination and the folding state are retained after oxidation.The complex exhibits superior SOD activity which was studied by sequential stopped-flow method.Thorough analysis of the data shows that the Ni(Ⅲ)species rapidly accumulates in the nickel catalyzed decomposition of superoxide anion.Accordingly,the presence of the penicillamine moiety close to the catalytic center increases the life-time of the Ni(Ⅲ)transient species.In contrast,Ni(Ⅲ)exists only at relatively low concentration level in the dismutation reaction catalyzed by the native NiSOD enzyme fragment.
基金funded by the Hungarian National Research,Development and Innovation Office(FK-134551,K-124544 and K-134694)projects.F.K.K.acknowledges financial support from the János Bolyai Research Scholarship of the Hungarian Academy of Sciencessupported by theÚNKP-21-5(F.K.K.)andÚNKP-21-4-Ⅱ(N.L.)New National Excellence Program of the Ministry for Innovation and Technology from the source of the National Research,Development and Innovation Fund.The authors are indebted to KIFÜfor providing access to resource based in Hungary.
文摘^(64)Cu is considered to be one of the most promising radioisotopes in radiotheranostics (combining therapeutics with diagnostics) because its positron emission is suitable for PET imaging while the combination of its β^(-) and Auger electrons delivers a therapeutic effect. In this work, we present a thorough coordination chemical characterization of two Cu(Ⅱ) complexes formed from the cross-bridged pentaazamacrocyclic CB-15aneN_(5) and its bifunctional derivative. The Cu(Ⅱ) chelates possess high thermodynamic stability, fast complexation and moderate inertness under harsh conditions (t_(1/2)=2.3 h, 5 M HCl, 50℃). EPR measurements and DFT calculations were carried out for characterizing their structure in solution. Furthermore, the radiolabeling experiments performed with ^(61)Cu(Ⅱ) confirmed the fast complexation even in the µM concentration range at pH=6.0. On the basis of these results, the CB-15aneN_(5) ligand family serves as an excellent platform for Cu(Ⅱ) complexation in radiotheranostics.
