Logo image
Design of a Ruthenium-Labeled Cytochrome c Derivative to Study Electron Transfer with the Cytochrome bc 1 Complex
Journal article   Peer reviewed

Design of a Ruthenium-Labeled Cytochrome c Derivative to Study Electron Transfer with the Cytochrome bc 1 Complex

Gregory Engstrom, Ray Rajagukguk, Aleister J. Saunders, Chetan N. Patel, Sany Rajagukguk, Torsten Merbitz-Zahradnik, Kunhong Xiao, Gary J. Pielak, Bernard Trumpower, Chang-An Yu, …
Biochemistry (Easton), v 42(10), pp 2816-2824
18 Mar 2003

Abstract

A new ruthenium-cytochrome c derivative was designed to study electron transfer from cytochrome bc1 to cytochrome c (Cc). The single sulfhydryl on yeast H39C;C102T iso-1-Cc was labeled with Ru(2,2‘-bipyrazine)2(4-bromomethyl-4‘-methyl-2,2‘-bipyridine) to form Ruz-39-Cc. The Ruz-39-Cc derivative has the same steady-state activity with yeast cytochrome bc1 as wild-type yeast iso-1-Cc, indicating that the ruthenium complex does not interfere in the binding interaction. Laser excitation of reduced Ruz-39-Cc results in electron transfer from heme c to the excited state of ruthenium with a rate constant of 1.5 × 106 s-1. The resulting Ru(I) is rapidly oxidized by atmospheric oxygen in the buffer. The yield of photooxidized heme c is 20% in a single flash. Flash photolysis of a 1:1 complex between reduced yeast cytochrome bc1 and Ruz-39-Cc at low ionic strength leads to rapid photooxidation of heme c, followed by intracomplex electron transfer from cytochrome c1 to heme c with a rate constant of 1.4 × 104 s-1. As the ionic strength is raised above 100 mM, the intracomplex phase disappears, and a new phase appears due to the bimolecular reaction between solution Ru-39-Cc and cytochrome bc1. The interaction of yeast Ru-39-Cc with yeast cytochrome bc1 is stronger than that of horse Ru-39-Cc with bovine cytochrome bc1, suggesting that nonpolar interactions are stronger in the yeast system.

Metrics

9 Record Views
44 citations in Scopus

Details

UN Sustainable Development Goals (SDGs)

This publication has contributed to the advancement of the following goals:

#3 Good Health and Well-Being
#13 Climate Action

InCites Highlights

Data related to this publication, from InCites Benchmarking & Analytics tool:

Collaboration types
Domestic collaboration
Web of Science research areas
Biochemistry & Molecular Biology
Logo image