Proton binding within a membrane protein by a protonated water cluster.

ABSTRACT: Proton transfer is crucial for many enzyme reactions. Here, we show that in addition to protonatable amino acid side chains, water networks could constitute proton-binding sites in proteins. A broad IR continuum absorbance change during the proton pumping photocycle of bacteriorhodopsin (bR) indicates most likely deprotonation of a protonated water cluster at the proton release site close to the surface. We investigate the influence of several mutations on the proton release network and the continuum change, to gain information about the location and extent of the protonated water network and to reveal the participating residues necessary for its stabilization. We identify a protonated water cluster consisting in total of one proton and about five water molecules surrounded by six side cha

SUBMITTER: Garczarek F 

PROVIDER: S-EPMC553315 | biostudies-literature | 2005 Mar

REPOSITORIES: biostudies-literature