Asymmetric structure of the yeast F1 ATPase in the absence of bound nucleotides

Abstract

The crystal structure of nucleotide-free yeast F1 ATPase has been determined at a resolution of 3.6Å. The overall structure is very similar to that of the ground state enzyme. In particular, the β DP and βTP subunits both adopt the closed conformation found in the ground state structure despite the absence of bound nucleotides. This implies that interactions between the γ and β subunits are as important as nucleotide occupancy in determining the conformational state of the β subunits. Furthermore, this result suggests that for the mitochondrial enzyme, there is no state of nucleotide occupancy that would result in more than one of the β subunits adopting the open conformation. The adenine-binding pocket of the βTP subunit is disrupted in the apoenzyme, suggesting that the βDP subunit is responsible for unisite catalytic activity. © 2009 by The American Society for Biochemistry and Molecular Biology, Inc.