REDOX INTERACTIONS IN CYTOCHROME-C-OXIDASE - FROM THE NEOCLASSICAL TOWARD MODERN MODELS

被引:23
作者
HENDLER, RW
WESTERHOFF, HV
机构
[1] UNIV AMSTERDAM, EC SLATER INST BIOCHEM RES, 1066 CX AMSTERDAM, NETHERLANDS
[2] NHLBI, CELL BIOL LAB, BETHESDA, MD 20892 USA
[3] NETHERLANDS CANC INST, DIV MOLEC BIOL, 1066 CX AMSTERDAM, NETHERLANDS
关键词
D O I
10.1016/S0006-3495(92)81748-4
中图分类号
Q6 [生物物理学];
学科分类号
071011 ;
摘要
Because of recent experimental data on the redox characteristics of cytochrome c oxidase and renewed interest in the role of cooperativity in energy coupling, the question of redox cooperativity in cytochrome c oxidase is reexamined. Extensive redox cooperativity between more than two redox centers, some of which are spectrally invisible, may be expected for this electron transfer coupled proton pump. Such cooperativity, however, cannot be revealed by the traditional potentiometric experiments based on a difference in absorbance between two wavelengths. Multiwavelength analyses utilizing singular value decomposition and second derivatives of absorbance vs. wavelength have revealed a stronger cooperativity than consistent with the ''neoclassical'' model, which allowed only for weak negative cooperativity between two equipotential one-electron centers. A thermodynamic analysis of redox cooperativity is developed, which includes the possibilities of strong cooperative redox interactions, the involvement of invisible redox centers, conformational changes, and monomer/dimer equilibrations. The experimental observation of an oxidation of one of the cytochromes (a3) with a decrease in applied redox potential is shown to require both strong negative cooperativity and the participation of more than two one-electron centers. A number of ''modern'' models are developed using the analytical approaches described in this paper. By testing with experimental data, some of these models are falsified, whereas some are retained with suggestions for further testing.
引用
收藏
页码:1586 / 1604
页数:19
相关论文
共 51 条
[1]  
BAKER GM, 1987, J BIOL CHEM, V262, P595
[2]   ANALYSIS OF THE CU, FE, AND ZN CONTENTS IN CYTOCHROME-C OXIDASES FROM DIFFERENT SPECIES AND TISSUES BY PROTON-INDUCED X-RAY-EMISSION (PIXE) [J].
BOMBELKA, E ;
RICHTER, FW ;
STROH, A ;
KADENBACH, B .
BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS, 1986, 140 (03) :1007-1014
[3]  
BRUNORI M, 1988, ADV INORG BIOCHEM, V7, P93
[4]  
CAUGHEY WS, 1976, ENZYMES, V13, P299
[5]   THERMODYNAMICS OF LOCAL LINKAGE EFFECTS - CONTRACTED PARTITION-FUNCTIONS AND THE ANALYSIS OF SITE-SPECIFIC ENERGETICS [J].
DICERA, E .
BIOPHYSICAL CHEMISTRY, 1990, 37 (1-3) :147-164
[6]   ZINC IS A CONSTITUENT OF BOVINE HEART CYTOCHROME-C OXIDASE PREPARATIONS [J].
EINARSDOTTIR, O ;
CAUGHEY, WS .
BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS, 1984, 124 (03) :836-842
[7]  
EINARSDOTTIR O, 1988, J BIOL CHEM, V263, P13641
[8]   BOVINE HEART CYTOCHROME-C OXIDASE PREPARATIONS CONTAIN HIGH-AFFINITY BINDING-SITES FOR MAGNESIUM AS WELL AS FOR ZINC, COPPER, AND HEME IRON [J].
EINARSDOTTIR, O ;
CAUGHEY, WS .
BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS, 1985, 129 (03) :840-847
[9]  
EINARSDOTTIR O, 1985, FED PROC, V44, P1780
[10]   A NEW HIGH-POTENTIAL REDOX TRANSITION FOR CYTOCHROME-AA3 [J].
HENDLER, RW ;
SIDHU, GS .
BIOPHYSICAL JOURNAL, 1988, 54 (01) :121-133