Rewiring photosynthesis: engineering wrong-way electron transfer in the purple bacterial reaction centre.
The purple bacterial reaction centre uses light energy to separate charge across the cytoplasmic membrane, reducing ubiquinone and oxidizing a c-type cytochrome. The protein possesses a macroscopic structural two-fold symmetry but displays a strong functional asymmetry, with only one of two available membrane-spanning branches of cofactors (the so-called A-branch) being used to catalyse photochemical charge separation. The factors underlying this functional asymmetry have been the subject of study for many years but are still not fully understood. Site-directed mutagenesis has been partially successful in rerouting electron transfer along the normally inactive B-branch, allowing comparison of the kinetics of equivalent electron transfer reactions on the two branches. Both the primary and secondary electron transfer steps on the B-branch appear to be considerably slower than their A-branch counterparts. The effectiveness of different mutations in rerouting electron transfer along the B-branch of cofactors is discussed.
Wakeham
M C
MC
Department of Biochemistry, School of Medical Sciences, University of Bristol, University Walk, Bristol, BS8 1TD, UK.
Jones
M R
MR
D001419:Bacteria / Q000378:metabolism*; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism; D045304:Cytochromes c / Q000378:metabolism; D004579:Electron Transport; D008958:Models, Molecular; D016296:Mutagenesis; D010084:Oxidation-Reduction; D010788:Photosynthesis; D045322:Photosynthetic Reaction Center Complex Proteins / Q000235:genetics / Q000378:metabolism*; D011487:Protein Conformation; D012242:Rhodobacter sphaeroides / Q000378:metabolism; D014451:Ubiquinone / Q000378:metabolism
D001426:Bacterial Proteins; D045322:Photosynthetic Reaction Center Complex Proteins; D014451:Ubiquinone; D045304:Cytochromes c