The mitochondrial ATP synthase inhibitor protein binds near the C‐terminus of the F1 β‐subunit

Abstract

The specific, mitochondrial ATP synthase protein (IF₁) was covalently cross-linked to its binding site on the catalytic sector of the enzyme (F₁-ATPase). The cross-linked complex was selectively cleaved, leaving IF₁ intact to facilitate the subsequent purification of the F₁ fragment to which IF₁ was cross-linked. This fragment was identified by sequence analysis as comprising residues 394–459 on the F₁ β-subunit, near the C-terminus. This finding is discussed in the light of secondary structure predictions for both IF₁ and the F₁ β-subunit, and sequence homologies between mitochondrial and other ATP synthases.