Electrostatic Environment of Proteorhodopsin Affects the pKa of Its Buried Primary Proton Acceptor.

ABSTRACT: The protonation state of embedded charged residues in transmembrane proteins (TMPs) can control the onset of protein function. It is understood that interactions between an embedded charged residue and other charged or polar residues in the moiety would influence its pKa, but how the surrounding environment in which the TMP resides affects the pKa of these residues is unclear. Proteorhodopsin (PR), a light-responsive proton pump from marine bacteria, was used as a model to examine externally accessible factors that tune the pKa of its embedded charged residue, specifically its primary proton acceptor D97. The pKa of D97 was compared between PR reconstituted in liposomes with different net headgroup charges and equilibrated in buffer with different ion concentrations. For PR reconstituted i

SUBMITTER: Han CT 

PROVIDER: S-EPMC7176579 | biostudies-literature | 2020 Apr

REPOSITORIES: biostudies-literature