NMR structure of the KaiC-interacting C-terminal domain of KaiA, a circadian clock protein: implications for KaiA-KaiC interaction.

ABSTRACT: KaiA is a two-domain circadian clock protein in cyanobacteria, acting as the positive element in a feedback loop that sustains the oscillation. The structure of the N-terminal domain of KaiA is that of a pseudo-receiver, similar to those of bacterial response regulators, which likely interacts with components of the clock-resetting pathway. The C-terminal domain of KaiA is highly conserved among cyanobacteria and enhances the autokinase activity of KaiC. Here we present the NMR structure of the C-terminal domain of KaiA from the thermophilic cyanobacterium Thermosynechococcus elongatus BP-1. This domain adopts a novel all alpha-helical homodimeric structure. Several mutations known to affect the period of the circadian oscillator are shown to be located at an exposed groove near the dimer

SUBMITTER: Vakonakis I 

PROVIDER: S-EPMC341745 | biostudies-literature | 2004 Feb

REPOSITORIES: biostudies-literature