Regulation of Interprotein Electron Transfer by Residue 82 of Yeast Cytochrome c

Publisher Website
Google Scholar
Abstract
Yeast iso-1-cytochrome c (Cc) mutants have been constructed with Phe, Tyr, Gly, Ser, Leu, and Ile at position 82, each with Thr substituted for Cys at position 102. Their long-range electron transfer with zinc-substituted cytochrome c peroxidase (ZnCcP) has been studied by two kinetic techniques. The charge-separated complex, [(ZnCcP) + ,Fe II Cc] converts to [ZnCcP,Fe III Cc] by a single, intracomplex electron transfer step that is not governed by "gating" through possible rapid dissociation of the complex or isomerization (for example, heme-ligand) by Fe II Cc subsequent to its formation from Fe III Cc. In every variant with an aliphatic residue at position 82 of Cc, the rate of this electron transfer process is ∼10 4 slower at ∼0°C than for the two variants with aromatic residues.

This publication has 28 references indexed in Scilit: