Protein-cofactor interactions in bacterial reaction centers from Rhodobacter sphaeroides R-26: I. Identification of the ENDOR lines associated with the hydrogen bonds to the primary quinone QA*-.

ABSTRACT: Hydrogen bonds are important in determining the structure and function of biomolecules. Of particular interest are hydrogen bonds to quinones, which play an important role in the bioenergetics of respiration and photosynthesis. In this work we investigated the hydrogen bonds to the two carbonyl oxygens of the semiquinone QA*- in the well-characterized reaction center from the photosynthetic bacterium Rhodobacter sphaeroides R-26. We used electron paramagnetic resonance and electron nuclear double resonance techniques at 35 GHz at a temperature of 80 K. The goal of this study was to identify and assign sets of 1H-ENDOR lines to protons hydrogen bonded to each of the two oxygens. This was accomplished by preferentially exchanging the hydrogen bond on one of the oxygens with deuterium while c

SUBMITTER: Flores M 

PROVIDER: S-EPMC1432105 | biostudies-literature | 2006 May

REPOSITORIES: biostudies-literature