Variety of KaiC Protein Clocks in Ocean Cyanobacteria

Cyanobacteria, unlike other prokaryotes, possess a circadian clock characterized by a unique three-protein oscillator.

• The circadian clock in Cyanobacteria is associated with 24-hour oscillations of KaiC phosphorylation.
• The freshwater cyanobacterium Synechococcus elongatus PCC 7942 serves as a well-documented model for this clock.
• Physiological studies suggest a circadian clock may also exist in various marine Cyanobacteria.
• Nearly all marine cyanobacterial species contain genes for the core clock components, though their specific compositions vary significantly.
• Comparative analysis highlights differences in timing mechanisms between Synechococcus elongatus and Prochlorococcus marinus.

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