Is the redox state of the ci heme of the cytochrome b6f complex dependent on the occupation and structure of the Qi site and vice versa?

The Journal of Biological Chemistry
Agnès de Lacroix de LavaletteFrancesca Zito

Abstract

Oxidoreductases of the cytochrome bc(1)/b(6)f family transfer electrons from a liposoluble quinol to a soluble acceptor protein and contribute to the formation of a transmembrane electrochemical potential. The crystal structure of cyt b(6)f has revealed the presence in the Q(i) site of an atypical c-type heme, heme c(i). Surprisingly, the protein does not provide any axial ligand to the iron of this heme, and its surrounding structure suggests it can be accessed by exogenous ligand. In this work we describe a mutagenesis approach aimed at characterizing the c(i) heme and its interaction with the Q(i) site environment. We engineered a mutant of Chlamydomonas reinhardtii in which Phe(40) from subunit IV was substituted by a tyrosine. This results in a dramatic slowing down of the reoxidation of the b hemes under single flash excitation, suggesting hindered accessibility of the heme to its quinone substrate. This modified accessibility likely originates from the ligation of the heme iron by the phenol(ate) side chain introduced by the mutation. Indeed, it also results in a marked downshift of the c(i) heme midpoint potential (from +100 mV to -200 mV at pH 7). Yet the overall turnover rate of the mutant cytochrome b(6)f complex und...Continue Reading

References

Feb 1, 1968·Zeitschrift Für Naturforschung. Teil B. Anorganische Chemie, Organische Chemie, Biochemie, Biophysik, Biologie·W Junge, H T Witt
Aug 23, 1974·Biochimica Et Biophysica Acta·P Joliot, R Delosme
Aug 1, 1982·Biochemical Society Transactions·A R Crofts, S W Meinhardt
Dec 8, 1995·The Journal of Biological Chemistry·Y PierreJ L Popot
Feb 14, 1995·Biochemistry·D P HildebrandA G Mauk
Jan 24, 1998·The Journal of Biological Chemistry·R KurasF A Wollman
Jul 1, 1998·Annual Review of Biophysics and Biomolecular Structure·M F PerutzG G Dodson
Aug 31, 2000·Annual Review of Biochemistry·E A BerryA R Crofts
Jun 19, 2002·Biochemistry·Florian MullerDavid M Kramer
Jul 18, 2002·Proceedings of the National Academy of Sciences of the United States of America·Pierre Joliot, Anne Joliot
May 1, 1956·The Biochemical Journal·J W CORNFORTH, A T JAMES
Dec 4, 2003·Nature·David StroebelDaniel Picot
Mar 9, 2004·Trends in Plant Science·John F Allen
Mar 31, 2004·Biochemistry·Catherine de VitryFrancis-André Wollman
Apr 9, 2005·Trends in Biochemical Sciences·Artur OsyczkaP Leslie Dutton
Oct 18, 2005·Photosynthesis Research·Elisabeth DarrouzetFevzi Daldal
Oct 26, 2005·Proceedings of the National Academy of Sciences of the United States of America·Jean AlricFabrice Rappaport
Dec 6, 2005·Photosynthesis Research·Antony R Crofts
Jan 5, 2007·Proceedings of the National Academy of Sciences of the United States of America·Frauke BaymannWolfgang Nitschke
May 15, 2007·Journal of Molecular Biology·E YamashitaW A Cramer
May 31, 2007·Proceedings of the National Academy of Sciences of the United States of America·Richard KurasCatherine de Vitry
May 14, 2008·Biochimica Et Biophysica Acta·A L DucluzeauF Baymann
Jun 19, 2008·Comptes rendus biologies·Agnès de Lacroix de LavaletteFrancesca Zito

❮ Previous
Next ❯

Citations

Jan 22, 2010·Photosynthesis Research·F Baymann, W Nitschke
Oct 29, 2013·Photosynthesis Research·Taras K AntalEsa Tyystjärvi
Jan 12, 2011·Bulletin of Mathematical Biology·Mark F Schumaker, David M Kramer
Nov 10, 2011·Biochemistry·Brian San FranciscoRobert G Kranz
May 11, 2011·Nature Communications·Alizée MalnoëFabrice Rappaport
Jun 15, 2010·Proteins·Lorna J SmithJanet M Thornton
May 12, 2017·Physiologia Plantarum·Daria V DibrovaArmen Y Mulkidjanian
Apr 9, 2020·The Biochemical Journal·Felix BuchertMichael Hippler
Jan 19, 2021·Biochimica Et Biophysica Acta. Bioenergetics·Lorna A MaloneMatthew P Johnson
Jun 3, 2021·Antioxidants·Tomás M FernandesCarlos A Salgueiro

❮ Previous
Next ❯

Related Concepts

Related Feeds

ASBMB Publications

The American Society for Biochemistry and Molecular Biology (ASBMB) includes the Journal of Biological Chemistry, Molecular & Cellular Proteomics, and the Journal of Lipid Research. Discover the latest research from ASBMB here.

Related Papers

Proceedings of the National Academy of Sciences of the United States of America
Frauke BaymannWolfgang Nitschke
Biochimica Et Biophysica Acta
A L DucluzeauFrauke Baymann
Photosynthesis Research
Frauke Baymann, Wolfgang Nitschke
© 2022 Meta ULC. All rights reserved