Pressure-Induced Structural Transition of Protein and Molecular Recognition

6 Pressure-Induced Structural Transition of Protein and Molecular Recognition 

Pressure denaturation of protein has been one of the problems in the focus of protein research due not only to its significance in science [47-49], but also to its importance in industrial applications, including food processing [50], The molecular mechanism of the process has not been clarified for a long time, especially concerning the role played by water or hydration. We have applied the RISM/3D-RISM theory to this problem to clarify the molecular mechanism behind the thermodynamics process [51]. 

Change in the equilibrium constant for the transition (N - D) between the native (N) and denatured (D) states of protein due to applied pressure can be described thermodynamically by 

The data shown in Fig. 10.8 are the PMV change upon the structural transition and its decomposition into different contributions obtained by the 3D-RISM theory [53]. The decomposition is made by the following equation, which was proposed first by Chalikian and Breslauer [54] and later redefined theoretically by us [23,55], 

The relation between the thermodynamics and the molecular process of pressure denaturation, clarified by the 3D-RISM theory, is as follows. At the low pressure condition in which all the calculations have been carried out, HPS is not the equilibrium conformation but is one of the fluctuating structures. 

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