****************OWARI COMPLEX SEMINAR LXXVII****************

Title: Theoretical estimation of cooperation among 
       elementary processes in clock proteins KaiABC 
       with construction of a reaction model

Speaker: Dr. KODA Shin-ichi

Affiliation: Institute for Molecular Science

Date: Tue. Feb. 27th, 3:00 pm (Almost one hour)

Place: 3rd Lecture Room (1F), Graduate School of Informatics

Abstract:
Biological clock of cyanobacteria is composed of three 
proteins, KaiA, KaiB and KaiC, where KaiC is periodically 
(de)phosphorylated. In this clock, local and fast ATP 
hydrolysis in KaiC induces conformational changes and 
(dis)assembly of proteins, and generates the global and 
long-period collective oscillation of phosphorylation state.
It is one of the main aims to elucidate how the 
spatio-temporal hierarchies of motion cooperate and 
generate the biological clock. In this talk, I will present 
a theoretical treatment to estimate the cooperation among 
the various elementary processes and their rate/equilibrium 
constants from experimental data. In this estimation, we 
constructed a reaction model of the periodic phosphorylation 
as a set of rate equations of elementary reactions and 
processes. Here, we picked up some experimental facts that 
might be key factors to generate the clock. Next, we carried 
out a parameter fitting so that outputs of the model and 
experimental data coincide. In this fitting, rate/equilibrium 
constants are treated as parameters and semi-automatically 
optimized. I will also discuss in this talk the result of 
the theoretical estimation suggesting that the three main 
properties (oscillation, temperature compensation of period, 
entrainment to periodical perturbation from environment) of 
the biological clock are generated by controlling ADP/ATP 
exchange rate in KaiC.

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