Spectroscopical identification of residues of subunit G of the yeast V-ATPase in its connection with subunit E

Mol Membr Biol. 2008 Aug;25(5):400-10. doi: 10.1080/09687680802183434.

Abstract

A critical point in the V(1) sector and entire V(1)V(O) complex is the interaction of stalk subunits G (Vma10p) and E (Vma4p). Previous work, using precipitation assays, has shown that both subunits form a complex. In this work, we have analysed the N-terminal segment of subunit G (G(1-59)) of the V(1)V(O) ATPase from Saccharomyces cerevisiae by using nuclear magnetic resonance (NMR) spectroscopy. Analyses of (1)H-(15)N heteronuclear single quantum coherence (HSQC) spectra of G(1-59) in the absence and presence of the N-terminal peptides E(1-18) and E(18-38) as well as the produced and purified C-terminal segment (E(39-233)) shows specific interactions only with the peptide fragment E(18-38). The binding of this peptide occurs via the residues M(1), V(2), S(3), and K(5) as well for V(22), S(23), K(24), A(25) and R(26) of G(1-59). The specific E(18-38)/G(1-59) binding has been confirmed by fluorescence correlation spectroscopy data. The E(18-38) peptide has been studied by CD spectroscopy and NMR. The 3D structure of this peptide adopts a stable helix-hinge-helix formation in solution. A model structure of the E(18-38)/G(1-59) complex reveals the orientation of E(18-38) relative to G(1-59) via salt-bridges of the polar residues and van der Waals forces at the very N-terminus of both segments.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Circular Dichroism
  • Models, Molecular*
  • Nuclear Magnetic Resonance, Biomolecular
  • Peptides / chemistry*
  • Protein Structure, Quaternary / physiology
  • Protein Structure, Secondary / physiology
  • Protein Structure, Tertiary / physiology
  • Saccharomyces cerevisiae / enzymology*
  • Saccharomyces cerevisiae Proteins / chemistry*
  • Vacuolar Proton-Translocating ATPases / chemistry*

Substances

  • Peptides
  • Saccharomyces cerevisiae Proteins
  • VMA10 protein, S cerevisiae
  • Vacuolar Proton-Translocating ATPases