4rnd

Publication Abstract from PubMed

Eukaryotic V1VO-ATPases hydrolyze ATP in the V1 domain coupled to ion pumping in VO. A unique mode of regulation of V-ATPases is the reversible disassembly of V1 and VO, which reduces ATPase activity and causes silencing of ion conduction. The subunits D and F are proposed to be key in these enzymatic processes. Here, we describe the structures of two conformations of the subunit DF assembly of Saccharomyces cerevisiae (ScDF) V-ATPase at 3.1 A resolution. Subunit D (ScD) consists of a long pair of alpha-helices connected by a short helix ((79)IGYQVQE(85)) as well as a beta-hairpin region, which is flanked by two flexible loops. The long pair of helices is composed of the N-terminal alpha-helix and the C-terminal helix, showing structural alterations in the two ScDF structures. The entire subunit F (ScF) consists of an N-terminal domain of four beta-strands (beta1-beta4) connected by four alpha-helices (alpha1-alpha4). alpha1 and beta2 are connected via the loop (26)GQITPETQEK(35), which is unique in eukaryotic V-ATPases. Adjacent to the N-terminal domain is a flexible loop, followed by a C-terminal alpha-helix (alpha5). A perpendicular and extended conformation of helix alpha5 was observed in the two crystal structures and in solution x-ray scattering experiments, respectively. Fitted into the nucleotide-bound A3B3 structure of the related A-ATP synthase from Enterococcus hirae, the arrangements of the ScDF molecules reflect their central function in ATPase-coupled ion conduction. Furthermore, the flexibility of the terminal helices of both subunits as well as the loop (26)GQITPETQEK(35) provides information about the regulatory step of reversible V1VO disassembly.

Crystal Structure of Subunits D and F in Complex Gives Insight into Energy Transmission of the Eukaryotic V-ATPase from Saccharomyces cerevisiae.,Balakrishna AM, Basak S, Manimekalai MS, Gruber G J Biol Chem. 2015 Feb 6;290(6):3183-96. doi: 10.1074/jbc.M114.622688. Epub 2014, Dec 12. PMID:25505269^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.