Thermodynamic investigations of cytochrome b5 unfolding. I. The tryptic fragment of cytochrome b5.


Abstract

Thermal unfolding of the tryptic fragment of the membrane-bound protein, cytochrome b5, which contains the residues 1-90, was investigated by scanning calorimetry, circular dichroism and absorption spectroscopy. The fragment undergoes a reversible two-state transition at about 70 degrees C (neutral pH). The fragment exhibits all the thermodynamic properties of small globular proteins with respect to heat capacity and transitional changes of enthalpy, Gibbs energy and heat capacity. The heat capacity change at unfolding fits into the correlation with the specific amount of nonpolar contacts, which has been found to be valid for small globular proteins (Privalov, P.L. and Khechinashvili, N.N. (1974) J. Mol. Biol. 86, 665-684). The relatively low stabilization energy of the cytochrome b5 fragment (delta trsG25 degrees C = 25 kJ/mol) is discussed in terms of the functional requirements of electron-transfer proteins. Study holds ProTherm entries: 11523, 11524 Extra Details: fragment contains the residues 1-90 membrane-bound protein; two-state transition; nonpolar contacts;,electron-transfer proteins

Submission Details

ID: QTYeMDoy

Submitter: Connie Wang

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

Version: 1

Publication Details
Pfeil W;Bendzko P,Biochim. Biophys. Acta (1980) Thermodynamic investigations of cytochrome b5 unfolding. I. The tryptic fragment of cytochrome b5. PMID:7459384
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