Abstract

To understand the stabilization mechanism of the transient intermediate state in protein folding, it is very important to understand the structure and stability of the molten globule state under a native condition, in which the native state exists stably. The thermal transitions of horse cytochrome c were thermodynamically evaluated by highly precise differential scanning calorimetry (DSC) at pH 3.8-5.0. The heat capacity functions were analyzed using double deconvolution and the nonlinear least-squares method. An intermediate (I) state is clearly confirmed in the thermal native (N)-to-denatured (D) transition of horse cytochrome c. The mole fraction of the intermediate state shows the largest value, 0.4, at nearly 70 degrees C at pH 4.1. This intermediate state was also detected by the circular dichroism (CD) method and was found to have the properties of the molten globule-like structure by three-state analysis of the CD data. The Gibbs free-energy change between N and I, DeltaG(NI), and that between N and D, DeltaG(ND), were evaluated to be 9-22 kJ mol(-1) and 41-45 kJ mol(-1), respectively at 15( ) degrees C and pH 4.1. Study holds ProTherm entries: 22787, 22788, 22789, 22790, 22791, 22792, 22793, 22794, 22795 Extra Details: Native to intermediate Molten globule; Cytochrome c; Differential scanning calorimetry; Circular dichroism; Thermal transition; Gibbs free energy change

Submission Details

ID: kc6cCSJX3

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:53 p.m.

Version: 1

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