Metal ions are essential to the structure and physiological functions of bacteriorhodopsin.Experimental evidence suggests the existence of specific cation binding to the negatively charged groups of Asp85 and Asp212 v...Metal ions are essential to the structure and physiological functions of bacteriorhodopsin.Experimental evidence suggests the existence of specific cation binding to the negatively charged groups of Asp85 and Asp212 via an electrostatic interaction.However,only using electrostatic force is not enough to explain the role of the metal cations because the carboxylate of Asp85 is well known to be protonated in the M intermediate.Considering the presence of some aromatic amino acid residues in the vicinity of the retinal pocket,the existence of cation-πinteractions between the metal cation and aromatic amino acid residues is suggested.Obviously,introduction of this kind of interaction is conducive to understanding the effects of the metal cations and aromatic amino acid residues inside the protein on the structural stability and proton pumping of bacteriorhodopsin.展开更多
A thin oriented bacteriorhodopsin(bR)film is deposited on a stainless steel slide by use of the electrophoretic sedimentation method.A junction is made with electrolyte gels having a counterelectrode to construct a bR...A thin oriented bacteriorhodopsin(bR)film is deposited on a stainless steel slide by use of the electrophoretic sedimentation method.A junction is made with electrolyte gels having a counterelectrode to construct a bR-based photoelectric detector.The photoelectric response signal to a 10ns laser pulse is measured.A theory on the photoelectric kinetics of bR is developed based on the concept of the charge displacement current and the bR photocycle rate equations.Comparison between the theoretical and experimental results proves that the bR photoelectric response to a short laser pulse is a multi-exponential process.The decay time constants and amplitudes of each exponential component are obtained by data fitting.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No.69731010the Key Program from Chinese Academy of Sciences under Grant Nos.Kj951-Al-501-05 and Kj952-Sl-03.
文摘Metal ions are essential to the structure and physiological functions of bacteriorhodopsin.Experimental evidence suggests the existence of specific cation binding to the negatively charged groups of Asp85 and Asp212 via an electrostatic interaction.However,only using electrostatic force is not enough to explain the role of the metal cations because the carboxylate of Asp85 is well known to be protonated in the M intermediate.Considering the presence of some aromatic amino acid residues in the vicinity of the retinal pocket,the existence of cation-πinteractions between the metal cation and aromatic amino acid residues is suggested.Obviously,introduction of this kind of interaction is conducive to understanding the effects of the metal cations and aromatic amino acid residues inside the protein on the structural stability and proton pumping of bacteriorhodopsin.
基金Supported by the Foundation of State Key Laboratory of Transient Optics and Technology under Grant No.YAK9705the President Foundation of Chinese Academy of Sciences under Grant No.40007059.
文摘A thin oriented bacteriorhodopsin(bR)film is deposited on a stainless steel slide by use of the electrophoretic sedimentation method.A junction is made with electrolyte gels having a counterelectrode to construct a bR-based photoelectric detector.The photoelectric response signal to a 10ns laser pulse is measured.A theory on the photoelectric kinetics of bR is developed based on the concept of the charge displacement current and the bR photocycle rate equations.Comparison between the theoretical and experimental results proves that the bR photoelectric response to a short laser pulse is a multi-exponential process.The decay time constants and amplitudes of each exponential component are obtained by data fitting.
