The CopC protein from pseudomonas syringae pathovar tomato is expressed as one of four proteins encoded by the operon CopABCD that is responsible for copper resistance. And there are one trypto-phan (83), one tyrosine...The CopC protein from pseudomonas syringae pathovar tomato is expressed as one of four proteins encoded by the operon CopABCD that is responsible for copper resistance. And there are one trypto-phan (83), one tyrosine (79), and three phenylalanines (35, 43, 99) in apoCopC. The fluorescence peak of apoCopC is located near 320 nm, and the peak shifts toward 353 nm in the presence of 10 mmol·L^(-1) urea with excitation at 280 nm. Using urea as a chemical agent, the conformational stabilities of apoCopC and Cu_N^(2+) -CopC were monitored by fluorescence spectrum in 20 mmol·L^(-1) phosphate buffer and 100 mmol·L^(-1) sodium chloride at pH 6.0. The free energy of stabilization for apoCopC and Cu_N^(2+)-CopC is 16.29±0.65 kJ·mol^(-1) and 26.26±0.35 kJ·mol^(-1), respectively. The distance between the tryptophan residue and the Cu^(2+) in Cu_N^(2+) -CopC has been studied by observing Frster type nonradia-tive energy transfer. And it is calculated to be 11.6 .展开更多
基金Supported by the National Natural Science Foundation of China (Grant No.20371031)the Natural Science Foundation of Shanxi Province (Grant No.20031017)
文摘The CopC protein from pseudomonas syringae pathovar tomato is expressed as one of four proteins encoded by the operon CopABCD that is responsible for copper resistance. And there are one trypto-phan (83), one tyrosine (79), and three phenylalanines (35, 43, 99) in apoCopC. The fluorescence peak of apoCopC is located near 320 nm, and the peak shifts toward 353 nm in the presence of 10 mmol·L^(-1) urea with excitation at 280 nm. Using urea as a chemical agent, the conformational stabilities of apoCopC and Cu_N^(2+) -CopC were monitored by fluorescence spectrum in 20 mmol·L^(-1) phosphate buffer and 100 mmol·L^(-1) sodium chloride at pH 6.0. The free energy of stabilization for apoCopC and Cu_N^(2+)-CopC is 16.29±0.65 kJ·mol^(-1) and 26.26±0.35 kJ·mol^(-1), respectively. The distance between the tryptophan residue and the Cu^(2+) in Cu_N^(2+) -CopC has been studied by observing Frster type nonradia-tive energy transfer. And it is calculated to be 11.6 .
