A molten globule-like intermediate state detected in the thermal transition of cytochrome c under low salt concentration.


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

Publication Details
Nakamura S;Baba T;Kidokoro S,Biophys. Chem. (2007) A molten globule-like intermediate state detected in the thermal transition of cytochrome c under low salt concentration. PMID:17257735
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