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Calculation of pigment transition energies in the FMO protein

Authors :
Mohamed Madjet
Frank Müh
Thomas Renger
Julia Adolphs
Source :
Photosynthesis Research. 95:197-209
Publication Year :
2007
Publisher :
Springer Science and Business Media LLC, 2007.

Abstract

The Fenna-Matthews-Olson (FMO) protein of green sulfur bacteria represents an important model protein for the study of elementary pigment-protein couplings. We have previously used a simple approach [Adolphs and Renger (2006) Biophys J 91:2778-2797] to study the shift in local transition energies (site energies) of the FMO protein of Prosthecochloris aestuarii by charged amino acid residues, assuming a standard protonation pattern of the titratable groups. Recently, we have found strong evidence that besides the charged amino acids also the neutral charge density of the protein is important, by applying a combined quantum chemical/electrostatic approach [Müh et al. (2007) Proc Natl Acad Sci USA, in press]. Here, we extract the essential parts from this sophisticated method to obtain a relatively simple method again. It is shown that the main contribution to the site energy shifts is due to charge density coupling (CDC) between the pigments and their pigment, protein and water surroundings and that polarization effects for qualitative considerations can be approximated by screening the Coulomb coupling by an effective dielectric constant.

Details

ISSN :
15735079 and 01668595
Volume :
95
Database :
OpenAIRE
Journal :
Photosynthesis Research
Accession number :
edsair.doi.dedup.....286057cfb857460a39e09788a227d9e9
Full Text :
https://doi.org/10.1007/s11120-007-9248-z