The Big Picture
I study the molecular mechanisms that govern the function of the KaiABC circadian oscillator
The photosynthetic cyanobacteria S. elongatus has an internal time-tracking device consisting of three soluble proteins: KaiA, KaiB and KaiC, the interactions among which generate a stable 24 hour oscillation in the KaiC phosphorylation pattern that persists up to weeks in vitro and exhibits remarkable insensitivity to temperature variation. In order for such a coherent oscillation to take place, the various KaiC phosphorylation, nucleotide binding, and protein-protein interaction events must proceed in a somewhat orderly manner. However, very little is known at the atomic level of the structure and dynamics of the clock proteins that enable the ordered slow kinetics. In order to address this question, I use molecular dynamics simulations and kinetic models to characterize the various phosphoforms of KaiC and assess the computational predictions with biochemical methods.