Research Repository

Cytochrome c<inf>6A</inf>: Discovery, structure and properties responsible for its low haem redox potential

Worrall, JAR and Luisi, BF and Schlarb-Ridley, BG and Bendall, DS and Howe, CJ (2008) 'Cytochrome c<inf>6A</inf>: Discovery, structure and properties responsible for its low haem redox potential.' Biochemical Society Transactions, 36 (6). 1175 - 1179. ISSN 0300-5127

Full text not available from this repository.

Abstract

Cytochrome c6A is a unique dithio-cytochrome of green algae and plants. It has a very similar core structure to that of bacterial and algal cytochromes c6, but is unable to fulfil the same function of transferring electrons from cytochrome f to Photosystem I. A key feature of cytochrome c6A is that its haem midpoint potential is more than 200 mV below that of cytochrome c6 (Em ≈ +340 mV) despite both cytochromes having histidine and methionine residues as axial haem-iron ligands. One salient difference between the haem pockets is that a valine residue in cytochrome c6A replaces a highly conserved glutamine residue in cytochrome c6. This difference has been probed using site-directed mutagenesis, X-ray crystallography and protein film voltammetry studies. It has been found that the stereochemistry of the glutamine residue within the haem pocket has a destabilizing effect and is responsible for tuning the haem's midpoint potential by over 100 mV. This large effect may have contributed to the evolution of a new biological function for cytochrome c6A. © 2008 Biochemical Society.

Item Type: Article
Subjects: Q Science > QH Natural history > QH301 Biology
Divisions: Faculty of Science and Health > Life Sciences, School of
Depositing User: Jim Jamieson
Date Deposited: 23 Sep 2011 09:51
Last Modified: 07 Oct 2019 08:15
URI: http://repository.essex.ac.uk/id/eprint/1008

Actions (login required)

View Item View Item