4rnd

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== Publication Abstract from PubMed ==
== Publication Abstract from PubMed ==
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Subunit F of V-ATPases is proposed to undergo structural alterations during catalysis and reversible dissociation from the V1VO complex. Recently, we determined the low resolution structure of F from Saccharomyces cerevisiae V-ATPase, showing an N-terminal egg shape, connected to a C-terminal hook-like segment via a linker region. To understand the mechanistic role of subunit F of S. cerevisiae V-ATPase, composed of 118 amino acids, the crystal structure of the major part of F, F(1-94), was solved at 2.3 A resolution. The structural features were confirmed by solution NMR spectroscopy using the entire F subunit. The eukaryotic F subunit consists of the N-terminal F(1-94) domain with four-parallel beta-strands, which are intermittently surrounded by four alpha-helices, and the C terminus, including the alpha5-helix encompassing residues 103 to 113. Two loops (26)GQITPETQEK(35) and (60)ERDDI(64) are described to be essential in mechanistic processes of the V-ATPase enzyme. The (26)GQITPETQEK(35) loop becomes exposed when fitted into the recently determined EM structure of the yeast V1VO-ATPase. A mechanism is proposed in which the (26)GQITPETQEK(35) loop of subunit F and the flexible C-terminal domain of subunit H move in proximity, leading to an inhibitory effect of ATPase activity in V1. Subunits D and F are demonstrated to interact with subunit d. Together with NMR dynamics, the role of subunit F has been discussed in the light of its interactions in the processes of reversible disassembly and ATP hydrolysis of V-ATPases by transmitting movements of subunit d and H of the VO and V1 sector, respectively.
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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.
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Crystal and NMR structures give insights into the role and dynamics of subunit F of the eukaryotic V-ATPase from Saccharomyces cerevisiae.,Basak S, Lim J, Manimekalai MS, Balakrishna AM, Gruber G J Biol Chem. 2013 Apr 26;288(17):11930-9. doi: 10.1074/jbc.M113.461533. Epub 2013, Mar 8. PMID:23476018<ref>PMID:23476018</ref>
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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<ref>PMID:25505269</ref>
From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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==See Also==
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*[[ATPase|ATPase]]
== References ==
== References ==
<references/>
<references/>

Revision as of 08:04, 25 February 2015

Crystal Structure of the subunit DF-assembly of the eukaryotic V-ATPase.

4rnd, resolution 3.18Å

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