The thermodynamic characteristic of four‐heme cytochrome c in Rhodopseudomonas viridis reaction centers, as derived from a quantitative analysis of the differential absorption spectra in α‐domain

FEBS Letters

Dracheva, S.M.²  Shinkarev, V.P.¹  Drachev, A.L.¹ 

[1] Moscow State University, USSR Academy of Sciences, Moscow 119899, USSR;Institute of Microbiology, USSR Academy of Sciences, Moscow 119899, USSR

关键词: Reaction center;    Four-heme cytochrome;    Redox titration;    Deconvolution method;    (Rhodopseudomonas viridis);    RC;    reaction center;    Em;    midpoint redox potential;    Eh;    redox potential of medium;    cjr;    the concentration of the reduced state of jthheme;   

DOI  :  10.1016/0014-5793(90)80624-R

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

A method of decomposing of the absorption spectrum of four-heme cytochrome of a Rhodopseudomonas viridis reaction center preparation into spectra of individual components was used to estimate the degree of the reduction of hemes as a function of redox potential in the medium. The method enables an evaluation of the shape of redox-titration curves of each heme. The redox-titration curves derived by this approach are approximated well by a Nernst equation with n = 1 and E_m -values of 360 mV, 312 mV, 20 mV and less than −50 mV. For all of the redox species the values of midpoint potential estimates by the above method are in good agreement with those determined earlier using another procedure [Dracheva et al. (1988) Eur. J. Biochem. 171, 253-264]. The accuracy of deconvolution of data is within the experimental errors of the redox potential measurement.

【 授权许可】

Unknown