Thermodynamics of apocytochrome b5 unfolding.


Apocytochrome b5 from rabbit liver was studied by scanning calorimetry, limited proteolysis, circular dichroism, second derivative spectroscopy, and size exclusion chromatography. The protein is able to undergo a reversible two-state thermal transition. However, transition temperature, denaturational enthalpy, and heat capacity change are reduced compared with the holoprotein. Apocytochrome b5 stability in terms of Gibbs energy change at protein unfolding (delta G) amounts to delta G = 7 +/- 1 kJ/mol at 25 degrees C (pH 7.4) compared with delta G = 25 kJ/mol for the holoprotein. Apocytochrome b5 is a compact, native-like protein. According to the spectral data, the cooperative structure is mainly based in the core region formed by residues 1-35 and 79-90. This finding is in full agreement with NMR data (Moore, C.D. & Lecomte, J.T.J., 1993, Biochemistry 32, 199-207). Study holds ProTherm entries: 11521, 11522 Extra Details: apocytochrome b5; protein folding; scanning calorimetry; thermodynamics

Submission Details

ID: vYn8fuft3

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:42 p.m.

Version: 1

Publication Details
Pfeil W,Protein Sci. (1993) Thermodynamics of apocytochrome b5 unfolding. PMID:8401233
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