Resonance Raman characterization of <Emphasis Type="Italic">Rhodobacter capsulatus</Emphasis> reaction centers with lysine mutations near the accessory bacteriochlorophylls |
| |
Authors: | Lei?Chen Christine?Kirmaier Dewey?Holten Email author" target="_blank">David?F?BocianEmail author |
| |
Institution: | (1) Department of Chemistry, University of California, Riverside, CA 92521-0403, USA;(2) Department of Chemistry, Washington University, St. Louis, MO 63130-4899, USA |
| |
Abstract: | Lysine residues have been introduced into Rhodobacter capsulatus reaction centers at M-polypeptide position 201 and at L-polypeptide position 178. These positions are in the proximity of ring V of the accessory bacterochlorophylls BA and BB, respectively. Resonance Raman studies indicate that the introduction of a Lys residue at either position M201 or L178 results in structural perturbations to the BChl cofactors. Lys at L178 directly interacts with BB, most likely via a hydrogen bond. The hydrogen bonding interaction is consistent with enhanced B branch electron transfer that is observed in RCs from the S(L178)K/G(M201)D/L(M212)H triple mutant versus the G(M201)D/L(M212)H double mutant (C. Kirmaier et al. (1999) Biochemistry 38 11516–11530). In contrast, the introduction of a Lys at M201 does not result in hydrogen bonding to the BA cofactor, in contrast to the introduction of a His at M201 (L. Chen et al. (2004) J Phys Chem 3 108: 0457–10464). Accordingly, the alkyl ammonium head group of the side chain of the Lys at M201 residue appears to be distant from BA. |
| |
Keywords: | charge separation dielectric constant free energy lysine replacements positive charge resonance Raman Rhodobacter capsulatus |
本文献已被 PubMed SpringerLink 等数据库收录! |
|