The modulation of cytochrome c electron self‐exchange by site‐specific chemical modification and anion binding

FEBS Letters

Concar, David W.²  Hill, H.Allen O.²  Moore, Geoffrey R.¹  Whitford, David²  Williams, Robert J.P.² 

[1] School of Chemical Sciences, University of East Anglia, Norwich NR4 7TJ, England;Inorganic Chemistry laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, England

关键词: Cytochrome;    c;    Chemical modification;    Electron transfer NMR;    Protein-protein interaction;    ATP;    ATP;    adenosine triphosphate;    CDNB;    4-chloro-3;    5-dinitrobenzoic acid;    CDNP;    4-chloro-3;    5-dinitrophenyl;    Co(CN)6 3−;    hexacyanocobaltate(III);    DSS;    sodium 2;    2-dimethyl-2-silapentane-5-sulphonate;    K;    lysine;   

DOI  :  10.1016/0014-5793(86)81331-X

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The site-specific chemical modification of horse heart cytochrome c at Lys-13 and -72 using 4-chloro-3,5-dinitrobenzoic acid (CDNB) increases the electron self-exchange rate of the protein. In the presence of 0.24 M cacodylate (pH^∗ 7.0) the electron self-exchange rate constants, k _ex, measured by a ₁H NMR saturation transfer method at 300 K, are 600, 6 × 10³ and 6 × 10⁴ M⁻¹·s⁻¹ for native, CDNP-K13 and CDNP-K72 cytochromes c respectively. Repulsive electrostatic interactions, which inhibit cytochrome c electron selfexchange, are differentially affected by modification. Measurements of ¹H NMR line broadening observed with partially oxidised samples of native cytochrome c show that ATP and the redox inert multivalent anion Co(CN)₆ ³⁻ catalyse electron self-exchange. At saturation a limiting value of ~ 1.4 × 10⁵ M⁻¹·s⁻¹ is observed for both anions.

【 授权许可】

Unknown