title: Primary structure and properties of the inhibitory protein of the mitochondrial ATPase (H(+)-ATP synthase) from potato.
abstract: The primary structure of the inhibitory protein (IF1) of the potato mitochondrial ATPase has been determined by protein sequencing, and its molecular weight determined by electrospray mass spectrometry. Both are consistent with a 56-residue protein of molecular weight 6697. This protein shows only weak homology with IF1 sequences from mammals and yeasts, and significant deletions are present compared to these sequences. Homology is strongest in the region between residues 22 and 46 (ox heart numbering), where 5 identities and 6 conserved residues are observed across all five IF1 species. In addition, this region shows homology with protein inhibitors from ATPases other than mitochondrial F1. It is suggested that this region might constitute an ATPase 'inhibitory motif'. Functional studies show that, unlike IF1 from mammals or yeasts, potato IF1 binds only poorly to ox heart F1, and does not show the ability to exist in 2 (alternate) stable conformations.
authors.affiliation: Department of Biochemistry, University of Oxford, UK.
authors.forename: K E
authors.initials: KE
authors.lastname: Polgreen
authors.forename: J
authors.initials: J
authors.lastname: Featherstone
authors.forename: A C
authors.initials: AC
authors.lastname: Willis
authors.forename: D A
authors.initials: DA
authors.lastname: Harris
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D006863:Hydrogen-Ion Concentration; D008928:Mitochondria / Q000201:enzymology*; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000737:chemistry*; D011487:Protein Conformation; D011506:Proteins / Q000737:chemistry*; D006180:Proton-Translocating ATPases / Q000037:antagonists & inhibitors* / Q000737:chemistry; D017386:Sequence Homology, Amino Acid; D011198:Solanum tuberosum / Q000201:enzymology*; D000097795:ATPase Inhibitory Protein
chemical_list: D010940:Plant Proteins; D011506:Proteins; D006180:Proton-Translocating ATPases; D000097795:ATPase Inhibitory Protein