Thermodynamics of apocytochrome b5 unfolding.


Abstract

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
Additional Information

Structure view and single mutant data analysis

Study data

No weblogo for data of varying length.
Colors: D E R H K S T N Q A V I L M F Y W C G P
 

Data Distribution

Studies with similar sequences (approximate matches)

Correlation with other assays (exact sequence matches)


Relevant PDB Entries

Structure ID Release Date Resolution Structure Title
2I96 2006-09-05T00:00:00+0000 0 Solution structure of the oxidized microsomal human cytochrome b5
1DO9 1999-12-20T00:00:00+0000 0 SOLUTION STRUCTURE OF OXIDIZED MICROSOMAL RABBIT CYTOCHROME B5. FACTORS DETERMINING THE HETEROGENEOUS BINDING OF THE HEME.
2M33 2013-01-08T00:00:00+0000 0 Solution NMR structure of full-length oxidized microsomal rabbit cytochrome b5
3X32 2015-01-14T00:00:00+0000 0.83 Crystal structure of the oxidized form of the solubilized domain of porcine cytochrome b5 in form 1 crystal
3X33 2015-01-14T00:00:00+0000 0.93 Crystal structure of the oxidized form of the solubilized domain of porcine cytochrome b5 in form 2 crystal
3X34 2015-01-14T00:00:00+0000 0.76 Crystal structure of the reduced form of the solubilized domain of porcine cytochrome b5 in form 1 crystal
3X35 2015-01-14T00:00:00+0000 0.95 Crystal structure of the reduced form of the solubilized domain of porcine cytochrome b5 in form 2 crystal
1AQA 1997-07-28T00:00:00+0000 0 SOLUTION STRUCTURE OF REDUCED MICROSOMAL RAT CYTOCHROME B5, NMR, MINIMIZED AVERAGE STRUCTURE
1AW3 1997-10-09T00:00:00+0000 0 THE SOLUTION NMR STRUCTURE OF OXIDIZED RAT MICROSOMAL CYTOCHROME B5, MINIMIZED AVERAGE STRUCTURE
1AXX 1997-10-22T00:00:00+0000 0 THE SOLUTION STRUCTURE OF OXIDIZED RAT MICROSOMAL CYTOCHROME B5, NMR, 19 STRUCTURES

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
93.1 Cytochrome b5 P00168 CYB5_ALOSE
90.4 Cytochrome b5 P56395 CYB5_MOUSE
92.6 Cytochrome b5 P00167 CYB5_HUMAN
91.5 Cytochrome b5 P00173 CYB5_RAT
93.6 Cytochrome b5 P00170 CYB5_HORSE
100.0 Cytochrome b5 P00169 CYB5_RABIT
90.3 Cytochrome b5 P00171 CYB5_BOVIN
93.6 Cytochrome b5 P00172 CYB5_PIG