Vanadyl as a probe of the function of the F1-ATPase-Mg2+ cofactor

Research output: Contribution to journalShort surveypeer-review

6 Scopus citations

Abstract

The Mg2+ dependent asymmetry of the F1-ATPase catalytic sites leads to the differences in affinity for nucleotides and is an essential component of the binding-change mechanism. Changes in metal ligands during the catalytic cycle responsible for this asymmetry were characterized by vanadyl (VIV = O)2+, a functional surrogate for Mg2+. The 51V-hyperfine parameters derived from EPR spectra of VO2+ bound to specific sites on F1 provide a direct probe of the metal ligands. Site-directed mutations of metal ligand residues cause measurable changes in the 51V-hyperfine parameters of the bound VO2+, thereby providing a means to identification. Initial binding of the metal-nucleotide to the low-affinity catalytic site conformation results in metal coordination by hydroxyl groups from the P-loop threonine and catch-loop threonine. Upon conversion to the high-affinity conformation, carboxyl groups from the Walker homology B aspartate and MF1βE197 become ligands in lieu of the hydroxyl groups.

Original languageEnglish (US)
Pages (from-to)539-546
Number of pages8
JournalJournal of Bioenergetics and Biomembranes
Volume32
Issue number5
DOIs
StatePublished - 2000

Keywords

  • F-ATPase
  • FF-ATP synthase
  • Vanadyl

ASJC Scopus subject areas

  • Physiology
  • Cell Biology

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