QUANTUM YIELD OF A 2-SITE PROTON DIFFUSION-MODEL - SUGGESTIONS FOR DOMINANT UNCOUPLING PROCESSES IN CYTOCHROME-OXIDASE

被引:2
作者
ARRECIS, JJ [1 ]
KUNDU, K [1 ]
PHILLIPS, P [1 ]
机构
[1] MIT,DEPT CHEM,CAMBRIDGE,MA 02139
关键词
D O I
10.1021/j100381a066
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
In this paper, we propose a two-redox-site diffusion model to examine the salient features of proton diffusion in the redox-driven proton pump cytochrome oxidase. The key problems addressed are proton diffusion in the presence of an electrostatic bias and the role of proton-uncoupling pathways. The proton quantum yield per electron transferred (H+/e-) is analyzed in the presence of the external bias with two spatially distinct forms of redox-proton uncoupling. Analysis of the proton quantum yield shows that the competition between proton diffusion and proton uncoupling results in the electron-transfer step being rate limiting in our model. In addition, the second redox site is utilized to control the access of the escape of the proton to solution. This feature may be ultimately important in controlling the proton backflows expected when the redox cycle is completed. © 1990 American Chemical Society.
引用
收藏
页码:7316 / 7321
页数:6
相关论文
共 21 条
[1]   REDOX-LINKED HYDROGEN-BOND STRENGTH CHANGES IN CYTOCHROME-A - IMPLICATIONS FOR A CYTOCHROME-OXIDASE PROTON PUMP [J].
BABCOCK, GT ;
CALLAHAN, PM .
BIOCHEMISTRY, 1983, 22 (10) :2314-2319
[2]  
BRUGER A, 1983, Z PHYS CHEM, V136, P1
[3]  
BRUNORI M, 1981, MET IONS BIOL SYST, V13, P187
[4]   THE MECHANISM OF ELECTRON GATING IN PROTON PUMPING CYTOCHROME-C-OXIDASE - THE EFFECT OF PH AND TEMPERATURE ON INTERNAL ELECTRON-TRANSFER [J].
BRZEZINSKI, P ;
MALMSTROM, BG .
BIOCHIMICA ET BIOPHYSICA ACTA, 1987, 894 (01) :29-38
[5]   CYTOCHROME-C OXIDASE - UNDERSTANDING NATURES DESIGN OF A PROTON PUMP [J].
CHAN, SI ;
LI, PM .
BIOCHEMISTRY, 1990, 29 (01) :1-12
[6]   THE PROTON-PUMPING SITE OF CYTOCHROME-C-OXIDASE - A MODEL OF ITS STRUCTURE AND MECHANISM [J].
GELLES, J ;
BLAIR, DF ;
CHAN, SI .
BIOCHIMICA ET BIOPHYSICA ACTA, 1986, 853 (3-4) :205-236
[7]   ELECTRON-TRANSFER BETWEEN BIOLOGICAL MOLECULES BY THERMALLY ACTIVATED TUNNELING [J].
HOPFIELD, JJ .
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 1974, 71 (09) :3640-3644
[8]   CHARGE SEPARATION EFFICIENCIES IN ARTIFICIAL PHOTOSYNTHETIC SYSTEMS - APPLICATION TO MOLECULARLY BASED ELECTRONIC DEVICES [J].
KUNDU, K ;
PHILLIPS, P .
JOURNAL OF CHEMICAL PHYSICS, 1988, 89 (09) :5922-5930
[9]  
MALMSTROM BG, 1987, CHEM SCRIPTA, V27B, P67
[10]   HYPOTHESIS - CYTOCHROME-C OXIDASE AS A PROTON PUMP - A TRANSITION-STATE MECHANISM [J].
MALMSTROM, BG .
BIOCHIMICA ET BIOPHYSICA ACTA, 1985, 811 (01) :1-12