Protein dynamics control the kinetics of initial electron transfer in photosynthesis.
The initial electron transfer dynamics during photosynthesis have been studied in Rhodobacter sphaeroides reaction centers from wild type and 14 mutants in which the driving force and the kinetics of charge separation vary over a broad range. Surprisingly, the protein relaxation kinetics, as measured by tryptophan absorbance changes, are invariant in these mutants. By applying a reaction-diffusion model, we can fit the complex electron transfer kinetics of each mutant quantitatively, varying only the driving force. These results indicate that initial photosynthetic charge separation is limited by protein dynamics rather than by a static electron transfer barrier.
Wang
Haiyu
H
Biodesign Institute, Arizona State University, 1001 South McAllister Avenue, Tempe, AZ 85287-5201, USA.
Lin
Su
S
Allen
James P
JP
Williams
Joann C
JC
Blankert
Sean
S
Laser
Christa
C
Woodbury
Neal W
NW
D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D001429:Bacteriochlorophylls / Q000378:metabolism; D004579:Electron Transport; D007700:Kinetics; D008027:Light; D008956:Models, Chemical; D009154:Mutation; D010788:Photosynthesis; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D012242:Rhodobacter sphaeroides / Q000235:genetics / Q000378:metabolism*; D013057:Spectrum Analysis; D013696:Temperature; D013816:Thermodynamics; D014364:Tryptophan / Q000737:chemistry
D001426:Bacterial Proteins; D001429:Bacteriochlorophylls; D045322:Photosynthetic Reaction Center Complex Proteins; D014364:Tryptophan