Differential influence of dynamic processes on forward and reverse electron transfer across a protein-protein interface

Brian M. Hoffman*, Laura M. Celis, Deborah A. Cull, Ami D. Patel, Jennifer L. Seifert, Korin E. Wheeler, Jingyun Wang, Jiang Yao, Igor V. Kurnikov, Judith M. Nocek

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

61 Scopus citations

Abstract

We propose that the forward and reverse halves of a flash-induced protein-protein electron transfer (ET) photocycle should exhibit differential responses to dynamic interconversion of configurations when the most stable configuration is not the most reactive, because the reactants exist in different initial configurations: the flash-photoinitiated forward ET process begins with the protein partners in an equilibrium ensemble of configurations, many of which have little or no reactivity, whereas the reactant of the thermal back ET (the charge-separated intermediate) is formed in a nonequilibrium, "activated" protein configuration. We report evidence for this proposal in measurements on (i) mixed-metal hemoglobin hybrids, (ii) the complex between cytochrome c peroxidase and cytochrome c, and (iii and iv) the complexes of myoglobin and isolated hemoglobin α-chains with cytochrome b5. For all three systems, forward and reverse ET does respond differently to modulation of dynamic processes; further, the response to changes in viscosity is different for each system.

Original languageEnglish (US)
Pages (from-to)3564-3569
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume102
Issue number10
DOIs
StatePublished - Mar 8 2005

Keywords

  • Cytochrome c
  • Cytochrome c peroxidase
  • Dynamics
  • Hemoglobin
  • Myoglobin

ASJC Scopus subject areas

  • General

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