BIOPHYSICAL THEORY AND MODELING |
A Quantitative Study of Lambda Phage SWITCH and its Components
Chunbo Lou 1, Xiaojing Yang 1, Xili Liu 1, Bin He 1 and Qi Ouyang 1*
1 Center for Theoretical Biology and School of Physics, Peking University
* To whom correspondence should be addressed. E-mail: qi{at}pku.edu.cn.
Submitted on September 9, 2006
Revised on October 17, 2006
Accepted on 19 December 2006
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Abstract |
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We propose a new model to quantitatively describe the lambda phage SWITCH system. The model incorporates facilitated transfer mechanism (FTM) of transcription factor, which can be simplified into a two-steps reaction. We first sequentially obtain two indispensable parameters by fitting our model to experimental data of two simple systems, and then apply them to study the natural lambda SWITCH system. By incorporating FTM, we find that in RecA- host E.coli the wild type lambda's lysogenic state is in a monostable regime rather than in a bistable regime. Furthermore, the model explains the weak role of Cro protein and probably shed light on the evolution of lambda Cro protein, which is known to be structurally distinct from the other Cros in lambdoid family members.
Key Words:
facilitated transfer mechanism, role of Cro, stability of lysogen
