Dynamic mechanisms driving conformational conversions of the ß and e subunits involved in rotational catalysis of F1-ATPase.

Proceedings of the Japan Academy. Series B, Physical and biological sciences

PubMedID: 29021512

Akutsu H. Dynamic mechanisms driving conformational conversions of the ß and e subunits involved in rotational catalysis of F1-ATPase. Proc Jpn Acad, Ser B, Phys Biol Sci. 2017;93(8):630-647.
F-type ATPase is a ubiquitous molecular motor. Investigations on thermophilic F1-ATPase and its subunits, ß and e, by NMR were reviewed. Using specific isotope labeling, pKa of the putative catalytic carboxylate in ß was estimated. Segmental isotope-labeling enabled us to monitor most residues of ß, revealing that the conformational conversion from open to closed form of ß on nucleotide binding found in ATPase was an intrinsic property of ß and could work as a driving force of the rotational catalysis. A stepwise conformational change was driven by switching of the hydrogen bond networks involving Walker A and B motifs. Segmentally labeled ATPase provided a well resolved NMR spectra, revealing while the open form of ß was identical for ß monomer and ATPase, its closed form could be different. ATP-binding was also a critical factor in the conformational conversion of e, an ATP hydrolysis inhibitor. Its structural elucidation was described.