Stable internal timing of the cyanobacteria’s daily clock inside cells and in lab tests

The period of over 20 KaiC period mutants ranged from 15 to 60 hours and was insensitive to environmental conditions.

• Circadian rhythms can maintain an approximately 24-hour period with precision, regardless of external factors like temperature.
• The reliability of in vivo circadian rhythms is influenced by both a protein-based oscillator and additional feedback mechanisms.
• KaiC ATPase activity correlates more strongly with circadian frequency in controlled lab conditions than in living organisms.
• The KaiC protein-based oscillator is suggested to encode a reliable circadian period independently of rhythm amplitude.
• Intrinsic properties of the circadian clock may help maintain stability and precision in timing within living cells.

Simplified