Effects of thermal fluctuation and the receptor-receptor interaction in bacterial chemotactic signaling and adaptation.

Bacterial chemotaxis is controlled by the conformational changes of the receptors in response to the change of the ambient chemical concentration. In a statistical mechanical approach, the signaling due to the conformational changes is a thermodynamic average quantity, dependent on the temperature and the total energy of the system, including both ligand-receptor interaction and receptor-receptor interaction. This physical theory suggests to biology an understanding of cooperation in ligand binding and receptor signaling problems. How much experimental support of this approach can be obtained from the currently available data? What are the parameter values? What is the practical information for experiments? Here we make comparisons between the theory and recent experimental results. Although currently comparisons can only be semiquantitative or qualitative, consistency is clearly shown. The theory also helps to sort a variety of data.