The structure of bovine F1-ATPase inhibited by ADP and beryllium fluoride

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Abstract
The structure of bovine F1‐ATPase inhibited with ADP and beryllium fluoride at 2.0 Å resolution contains two ADP.BeF3− complexes mimicking ATP, bound in the catalytic sites of the βTP and βDP subunits. Except for a 1 Å shift in the guanidinium of αArg373, the conformations of catalytic side chains are very similar in both sites. However, the ordered water molecule that carries out nucleophilic attack on the γ‐phosphate of ATP during hydrolysis is 2.6 Å from the beryllium in the βDP subunit and 3.8 Å away in the βTP subunit, strongly indicating that the βDP subunit is the catalytically active conformation. In the structure of F1‐ATPase with five bound ADP molecules (three in α‐subunits, one each in the βTP and βDP subunits), which has also been determined, the conformation of αArg373 suggests that it senses the presence (or absence) of the γ‐phosphate of ATP. Two catalytic schemes are discussed concerning the various structures of bovine F1‐ATPase.