Identification of two segments of the γ subunit of ATP synthase responsible for the different affinities of the catalytic nucleotide-binding sites.

ABSTRACT: ATP synthase uses a rotary mechanism to couple transmembrane proton translocation to ATP synthesis and hydrolysis, which occur at the catalytic sites in the β subunits. In the presence of Mg²⁺, the three catalytic sites of ATP synthase have vastly different affinities for nucleotides, and the position of the central γ subunit determines which site has high, medium, or low affinity. Affinity differences and their changes as rotation progresses underpin the ATP synthase catalytic mechanism. Here, we used a series of variants with up to 45- and 60-residue-long truncations of the N- and C-terminal helices of the γ subunit, respectively, to identify the segment(s) responsible for the affinity differences of the catalytic sites. We found that each helix carries an affinity-determining

SUBMITTER: Mnatsakanyan N 

PROVIDER: S-EPMC6349107 | biostudies-literature | 2019 Jan

REPOSITORIES: biostudies-literature