Covalent binding of 3′-O-(4-benzoyl)benzoyl adenosine 5′-triphosphate (BzATP) to the isolated α and β subunits and the α₃β₃ core complex of TF₁: Covalent binding of BzATP prevents association of α and β subunits and induces dissociation of the α₃β₃ core complex

Binding of the photoreactive ATP analog, 3′-O-(4-benzoyl)benzoyl adenosine 5′-triphosphate (BzATP), to the isolated α and β subunits of TF₁ and to the α₃β₃ "core" complex of the holoenzyme is described. About 1 mol of BzATP/mol of subunit was incorporated to isolated α and β subunits. The incorporation of BzATP was prevented by ATP. Covalent binding of BzATP to the α subunit was in general somewhat lower than that observed with the β subunit. No complex was formed upon mixing of either of the modified subunits with the complementary nontreated subunits. Covalent binding of 3 mol of BzATP/α₃β₃ complex completely inhibited ATPase activity and resulted in the dissociation of the complex. The labeled nucleotide analog was specifically incorporated into the β subunit of the complex. The holoenzyme TF₁, in contrast to the core complex, did not dissociate to the individual subunits upon covalent binding of BzATP. These results are discussed in relation to the location of the catalytic nucleotide binding site(s) and the conformation stability of the α₃β₃ core complex of TF₁.