title: Assembly of subunit d (Vma6p) and G (Vma10p) and the NMR solution structure of subunit G (G(1-59)) of the Saccharomyces cerevisiae V(1)V(O) ATPase.
abstract: Understanding the structural traits of subunit G is essential, as it is needed for V(1)V(O) assembly and function. Here solution NMR of the recombinant N- (G(1-59)) and C-terminal segment (G(61-114)) of subunit G, has been performed in the absence and presence of subunit d of the yeast V-ATPase. The data show that G does bind to subunit d via its N-terminal part, G(1-59) only. The residues of G(1-59) involved in d binding are Gly7 to Lys34. The structure of G(1-59) has been solved, revealing an alpha-helix between residues 10 and 56, whereby the first nine- and the last three residues of G(1-59) are flexible. The surface charge distribution of G(1-59) reveals an amphiphilic character at the N-terminus due to positive and negative charge distribution at one side and a hydrophobic surface on the opposite side of the structure. The C-terminus exhibits a strip of negative residues. The data imply that G(1-59)-d assembly is accomplished by hydrophobic interactions and salt-bridges of the polar residues. Based on the recently determined NMR structure of segment E(18-38) of subunit E of yeast V-ATPase and the presently solved structure of G(1-59), both proteins have been docked and binding epitopes have been analyzed.
authors.affiliation: School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Republic of Singapore.
authors.forename: Sankaranarayanan
authors.initials: S
authors.lastname: Rishikesan
authors.forename: Shovanlal
authors.initials: S
authors.lastname: Gayen
authors.forename: Youg R
authors.initials: YR
authors.lastname: Thaker
authors.forename: Subramanian
authors.initials: S
authors.lastname: Vivekanandan
authors.forename: Malathy S S
authors.initials: MS
authors.lastname: Manimekalai
authors.forename: Yin Hoe
authors.initials: YH
authors.lastname: Yau
authors.forename: Susana Geifman
authors.initials: SG
authors.lastname: Shochat
authors.forename: Gerhard
authors.initials: G
authors.lastname: Grüber