Structural mimicry confers robustness in the cyanobacterial circadian clock

摘要: Abstract The histidine kinase SasA enhances robustness of circadian rhythms in the cyanobacterium S. elongatus by temporally controlling expression core clock components, kaiB and kaiC. Here we show that also engages directly with KaiB KaiC proteins to regulate period enhance reconstituted oscillator vitro, particularly under limiting concentrations KaiB. In contrast its role regulating gene expression, function does not require activity; rather, uses structural mimicry cooperatively recruit rare, fold-switched conformation hexamer form nighttime repressive complex. Cooperativity gives way competition increasing define a dynamic window which modulates robustness. One Sentence Summary controls assembly protein complexes through balance cooperative competitive interactions.