Interaction between cytochrome c2 and the photosynthetic reaction center from Rhodobacter sphaeroides: role of interprotein hydrogen bonds in binding and electron transfer.

ABSTRACT: The role of short-range hydrogen bond interactions at the interface between electron transfer proteins cytochrome c(2) (cyt) and the reaction center (RC) from Rhodobacter sphaeroides was studied by mutation (to Ala) of RC residues Asn M187, Asn M188, and Gln L258 which form interprotein hydrogen bonds to cyt in the cyt-RC complex. The largest decrease in binding constant K(A) (8-fold) for a single mutation was observed for Asn M187, which forms an intraprotein hydrogen bond to the key residue Tyr L162 in the center of the contact region with a low solvent accessibility. Interaction between Asn M187 and Tyr L162 was also implicated in binding by double mutation of the two residues. The hydrogen bond mutations did not significantly change the second-order rate constant, k(2), indicating the

SUBMITTER: Abresch EC 

PROVIDER: S-EPMC2615004 | biostudies-literature | 2008 Dec

REPOSITORIES: biostudies-literature