Evolutionary origins of self-sustained Kai protein circadian oscillators in cyanobacteria.

ABSTRACT: Light-dark cycles affect photosynthetic efficiency in autotrophic cyanobacteria; therefore, determining whether ancient cyanobacteria possessed a self-sustained circadian clock when oxygenic photosynthetic systems were established is an important issue in chronobiology. Here we examine the oscillation of the clock protein KaiC in modern cyanobacteria, as well as the function and structure of ancestral Kai proteins, to determine the evolutionary origin of the self-sustained Kai-protein oscillators. The results show that the oldest double-domain KaiC in ancestral bacteria lacks the factors functionally and structurally essential for rhythmicity. The ancestral Kai proteins have acquired these factors through molecular evolution that occurred around Global Oxidation and Snowball Earth events,

SUBMITTER: Mukaiyama A 

PROVIDER: S-EPMC12081879 | biostudies-literature | 2025 May

REPOSITORIES: biostudies-literature