Isolated ε subunit of Bacillus subtilis F1-ATPase binds ATP

Abstract: Previously, we demonstrated ATP binding to the isolated ε subunit of F1-ATPase from thermophilic Bacillus PS3 [Kato-Yamada Y., Yoshida M. (2003) J. Biol. Chem. 278, 36013]. However, whether it is a general feature of the ε subunit from other sources is yet unclear. Here, using a sensitive method to detect weak interactions between fluorescently labeled ε subunit and nucleotide, it was shown that the ε subunit of F1-ATPase from Bacillus subtilis also bound ATP. The dissociation constant for ATP binding at room temperature was calculated to be 2mM, which may be suitable for sensing cellular ATP concentration in vivo. [Copyright &y& Elsevier]