λ噬菌体溶源/裂解转换调控与定态熵

被λ噬菌体感染的大肠杆菌是研究生物基因调控网络的重要模板之一. 根据该调控系统操纵子与调控蛋白相互作用特点, 利用热力学配分函数描述调控蛋白与操纵子的结合概率, 在给出该调控系统的动力学分岔的基础上, 计算系统各定态的热力学熵. 结果显示, 溶源态和裂解态较鞍点和分岔点具有更低的熵值, 且溶源态的熵最低, 说明处于溶源态的系统具有更高的生物序.     

Entropy Production Rate Changes in Lysogeny/Lysis Switch Regulation of Bacteriophage Lambda

According to the chemical kinetic model of lysogeny/lysis switch in Escherichia coli (E. coli) infected by bacteriophage λ, the entropy production rates of steady states are calculated. The results show that the lysogenic state has lower entropy production rate than lytic state, which provides an explanation on why the lysogenic state of λ phage is so stable. We also notice that the entropy production rates of both lysogenic state and lytic state are lower than that of saddle-point and bifurcation state, which is consistent with the principle of minimum entropy production for living organism in nonequilibrium stationary state. Subsequently, the relations between CI and Cro degradation rates at two bifurcations and the changes of entropy production rate with CI and Cro degradation are deduced. The theory and method can be used to calculate entropy change in other molecular network.