Solution structure and dynamics of the complex between cytochrome c and cytochrome c peroxidase determined by paramagnetic NMR

TitleSolution structure and dynamics of the complex between cytochrome c and cytochrome c peroxidase determined by paramagnetic NMR
Publication TypeJournal Article
Year of Publication2006
AuthorsVolkov, A.N., J.A.R. Worrall, E. Holtzmann, M. Ubbink
JournalProceedings of the National Academy of Sciences of the United States of America
Volume103
Issue50
Pagination18945-18950
Date PublishedDec 12
ISBN Number0027-8424
Accession NumberWOS:000242884200015
Keywordsbinding, brownian dynamics, crystal-structure, electron transfer, electron-transfer complex, encounter state, global fold determination, nuclear-magnetic-resonance, paramagnetic relaxation enhancement, protein-protein association, relaxation enhancement, site-directed spin, spin label, transient complex, yeast iso-1-cytochrome-c
Abstract

The physiological complex of yeast cytochrome c peroxidase and iso-1-cytochrome c is a paradigm for biological electron transfer. Using paramagnetic NMR spectroscopy, we have determined the conformation of the protein complex in solution, which is shown to be very similar to that observed in the crystal structure [Pelletier H, Kraut J (1992) Science 258:1748-1755]. Our results support the view that this transient electron transfer complex is dynamic. The solution structure represents the dominant protein-protein orientation, which, according to our estimates, is occupied for > 70% of the lifetime of the complex, with the rest of the time spent in the dynamic encounter state. Based on the observed paramagnetic effects, we have delineated the conformational space sampled by the protein molecules during the dynamic part of the interaction, providing experimental support for the theoretical predictions of the classical Brownian dynamics study [Northrup SH, Boles JO, Reynolds JCL (1988) Science 241:67-70]. Our findings corroborate the dynamic behavior of this complex and offer an insight into the mechanism of the protein complex formation in solution.

DOI10.1073/Pnas.0603551103
Alternate JournalP Natl Acad Sci USA

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