The ATP-mediated regulation of KaiB-KaiC interaction in the cyanobacterial circadian clock.

ABSTRACT: The cyanobacterial circadian clock oscillator is composed of three clock proteins--KaiA, KaiB, and KaiC, and interactions among the three Kai proteins generate clock oscillation in vitro. However, the regulation of these interactions remains to be solved. Here, we demonstrated that ATP regulates formation of the KaiB-KaiC complex. In the absence of ATP, KaiC was monomeric (KaiC(1mer)) and formed a complex with KaiB. The addition of ATP plus Mg(2+) (Mg-ATP), but not that of ATP only, to the KaiB-KaiC(1mer) complex induced the hexamerization of KaiC and the concomitant release of KaiB from the KaiB-KaiC(1mer) complex, indicating that Mg-ATP and KaiB compete each other for KaiC. In the presence of ATP and Mg(2+) (Mg-ATP), KaiC became a homohexameric ATPase (KaiC(6mer)) with bound Mg-ATP and f

SUBMITTER: Mutoh R 

PROVIDER: S-EPMC3823767 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature