Thermodynamics of barnase unfolding.


Abstract

The thermodynamics of barnase denaturation has been studied calorimetrically over a broad range of temperature and pH. It is shown that in acidic solutions the heat denaturation of barnase is well approximated by a 2-state transition. The heat denaturation of barnase proceeds with a significant increase of heat capacity, which determines the temperature dependencies of the enthalpy and entropy of its denaturation. The partial specific heat capacity of denatured barnase is very close to that expected for the completely unfolded protein. The specific denaturation enthalpy value extrapolated to 130 degrees C is also close to the value expected for the full unfolding. Therefore, the calorimetrically determined thermodynamic characteristics of barnase denaturation can be considered as characteristics of its complete unfolding and can be correlated with structural features--the number of hydrogen bonds, extent of van der Waals contacts, and the surface areas of polar and nonpolar groups. Using this information and thermodynamic information on transfer of protein groups into water, the contribution of various factors to the stabilization of the native structure of barnase has been estimated. The main contributors to the stabilization of the native state of barnase appear to be intramolecular hydrogen bonds. The contributions of van der Waals interactions between nonpolar groups and those of hydration effects of these groups are not as large if considered separately, but the combination of these 2 factors, known as hydrophobic interactions, is of the same order of magnitude as the contribution of hydrogen bonding. Study holds ProTherm entries: 3024 Extra Details: hydrogen bonding; hydrophobic interactions; barnase;,scanning microcalorimetry

Submission Details

ID: 4Pj2fo5Y3

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:20 p.m.

Version: 1

Publication Details
Griko YV;Makhatadze GI;Privalov PL;Hartley RW,Protein Sci. (1994) Thermodynamics of barnase unfolding. PMID:8003984
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
2KF6 2009-12-08 Barnase bound to d(CGAC) high pressure
2KF4 2009-12-08 Barnase high pressure structure
1BNR 1995-07-31 BARNASE
2KF3 2009-12-08 Barnase, low pressure reference NMR structure
1FW7 2003-06-10 NMR STRUCTURE OF 15N-LABELED BARNASE
2KF5 2009-12-08 Barnase bound to d(CGAC), low pressure
2C4B 2005-11-21 1.3 Inhibitor cystine knot protein McoEeTI fused to the catalytically inactive barnase mutant H102A
1A2P 1998-04-29 1.5 BARNASE WILDTYPE STRUCTURE AT 1.5 ANGSTROMS RESOLUTION
2ZA4 2008-05-20 1.58 Crystal Structural Analysis of Barnase-barstar Complex
1B20 1998-12-09 1.7 DELETION OF A BURIED SALT-BRIDGE IN BARNASE
1BRN 1994-01-31 1.76 SUBSITE BINDING IN AN RNASE: STRUCTURE OF A BARNASE-TETRANUCLEOTIDE COMPLEX AT 1.76 ANGSTROMS RESOLUTION
1B2X 1998-12-09 1.8 BARNASE WILDTYPE STRUCTURE AT PH 7.5 FROM A CRYO_COOLED CRYSTAL AT 100K
1B2S 1998-12-08 1.82 STRUCTURAL RESPONSE TO MUTATION AT A PROTEIN-PROTEIN INTERFACE
1X1Y 2005-04-26 1.9 Water-mediate interaction at aprotein-protein interface
1RNB 1992-07-15 1.9 CRYSTAL STRUCTURE OF A BARNASE-D(*GP*C) COMPLEX AT 1.9 ANGSTROMS RESOLUTION
1BRI 1995-07-10 1.9 BARNASE MUTANT WITH ILE 76 REPLACED BY ALA
3KCH 2010-03-09 1.94 Baranase crosslinked by glutaraldehyde
2F5M 2006-04-25 1.95 Cross-linked barnase soaked in bromo-ethanol
2F56 2006-04-25 1.96 Barnase cross-linked with glutaraldehyde soaked in 6M urea
1BRS 1994-06-22 2.0 PROTEIN-PROTEIN RECOGNITION: CRYSTAL STRUCTURAL ANALYSIS OF A BARNASE-BARSTAR COMPLEX AT 2.0-A RESOLUTION
1BSB 1994-01-31 2.0 CRYSTAL STRUCTURAL ANALYSIS OF MUTATIONS IN THE HYDROPHOBIC CORES OF BARNASE
1BRK 1995-07-10 2.0 BARNASE MUTANT WITH ILE 96 REPLACED BY ALA
1B21 1998-12-09 2.0 DELETION OF A BURIED SALT BRIDGE IN BARNASE
1BSC 1994-01-31 2.0 CRYSTAL STRUCTURAL ANALYSIS OF MUTATIONS IN THE HYDROPHOBIC CORES OF BARNASE
1BRH 1995-07-10 2.0 BARNASE MUTANT WITH LEU 14 REPLACED BY ALA
2F5W 2006-04-25 2.0 Cross-linked barnase soaked in 3 M thiourea
1BSA 1994-01-31 2.0 CRYSTAL STRUCTURAL ANALYSIS OF MUTATIONS IN THE HYDROPHOBIC CORES OF BARNASE
1BNF 1995-07-10 2.0 BARNASE T70C/S92C DISULFIDE MUTANT
1BRJ 1995-07-10 2.0 BARNASE MUTANT WITH ILE 88 REPLACED BY ALA
1BSE 1994-01-31 2.0 CRYSTAL STRUCTURAL ANALYSIS OF MUTATIONS IN THE HYDROPHOBIC CORES OF BARNASE
1B2Z 1998-12-09 2.03 DELETION OF A BURIED SALT BRIDGE IN BARNASE
1BNS 1994-06-22 2.05 STRUCTURAL STUDIES OF BARNASE MUTANTS
1BNE 1995-07-10 2.1 BARNASE A43C/S80C DISULFIDE MUTANT
1BNI 1995-09-15 2.1 BARNASE WILDTYPE STRUCTURE AT PH 6.0
1B2U 1998-12-09 2.1 STRUCTURAL RESPONSE TO MUTATION AT A PROTEIN-PROTEIN INTERFACE
1BNG 1995-07-10 2.1 BARNASE S85C/H102C DISULFIDE MUTANT
1BNJ 1995-09-15 2.1 BARNASE WILDTYPE STRUCTURE AT PH 9.0
1X1W 2005-04-26 2.1 Water-mediate interaction at aprotein-protein interface
1B27 1998-12-09 2.1 STRUCTURAL RESPONSE TO MUTATION AT A PROTEIN-PROTEIN INTERFACE
2F4Y 2006-04-25 2.15 Barnase cross-linked with glutaraldehyde
3Q3F 2012-01-25 2.17 Engineering Domain-Swapped Binding Interfaces by Mutually Exclusive Folding: Insertion of Ubiquitin into position 103 of Barnase
1BAN 1993-10-31 2.2 THE CONTRIBUTION OF BURIED HYDROGEN BONDS TO PROTEIN STABILITY: THE CRYSTAL STRUCTURES OF TWO BARNASE MUTANTS
1BAO 1993-10-31 2.2 THE CONTRIBUTION OF BURIED HYDROGEN BONDS TO PROTEIN STABILITY: THE CRYSTAL STRUCTURES OF TWO BARNASE MUTANTS
1YVS 1999-02-02 2.2 Trimeric domain swapped barnase
1BRG 1994-06-22 2.2 CRYSTALLOGRAPHIC ANALYSIS OF PHE->LEU SUBSTITUTION IN THE HYDROPHOBIC CORE OF BARNASE
3DA7 2009-04-14 2.25 A conformationally strained, circular permutant of barnase
1X1X 2005-04-26 2.3 Water-mediate interaction at aprotein-protein interface
1X1U 2005-04-26 2.3 Water-mediate interaction at aprotein-protein interface
1BSD 1994-01-31 2.3 CRYSTAL STRUCTURAL ANALYSIS OF MUTATIONS IN THE HYDROPHOBIC CORES OF BARNASE
1B3S 1998-12-09 2.39 STRUCTURAL RESPONSE TO MUTATION AT A PROTEIN-PROTEIN INTERFACE
1BGS 1994-04-30 2.6 RECOGNITION BETWEEN A BACTERIAL RIBONUCLEASE, BARNASE, AND ITS NATURAL INHIBITOR, BARSTAR

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
97.3 Ribonuclease P35078 RN_BACCI
100.0 Ribonuclease P00648 RNBR_BACAM