Structural energetics of barstar studied by differential scanning microcalorimetry.


Abstract

The energetics of barstar denaturation have been studied by CD and scanning microcalorimetry in an extended range of pH and salt concentration. It was shown that, upon increasing temperature, barstar undergoes a transition to the denatured state that is well approximated by a two-state transition in solutions of high ionic strength. This transition is accompanied by significant heat absorption and an increase in heat capacity. The denaturational heat capacity increment at approximately 75 degrees C was found to be 5.6 +/- 0.3 kJ K-1 mol-1. In all cases, the value of the measured enthalpy of denaturation was notably lower than those observed for other small globular proteins. In order to explain this observation, the relative contributions of hydration and the disruption of internal interactions to the total enthalpy and entropy of unfolding were calculated. The enthalpy and entropy of hydration were found to be in good agreement with those calculated for other proteins, but the enthalpy and entropy of breaking internal interactions were found to be among the lowest for all globular proteins that have been studied. Additionally, the partial specific heat capacity of barstar in the native state was found to be 0.37 +/- 0.03 cal K-1 g-1, which is higher than what is observed for most globular proteins and suggests significant flexibility in the native state. It is known from structural data that barstar undergoes a conformational change upon binding to its natural substrate barnase.(ABSTRACT TRUNCATED AT 250 WORDS) Study holds ProTherm entries: 2577, 2578, 2579 Extra Details: barstar; protein stability; scanning microcalorimetry

Submission Details

ID: E8RW3mHH

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:19 p.m.

Version: 1

Publication Details
Wintrode PL;Griko YV;Privalov PL,Protein Sci. (1995) Structural energetics of barstar studied by differential scanning microcalorimetry. PMID:8520478
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
1AB7 1997-09-04 NMR 15N RELAXATION AND STRUCTURAL STUDIES REVEAL CONFORMATIONAL EXCHANGE IN BARSTAR C40/82A, 30 STRUCTURES
1BTA 1994-07-31 THREE-DIMENSIONAL SOLUTION STRUCTURE AND 13C ASSIGNMENTS OF BARSTAR USING NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY
1BTB 1994-07-31 THREE-DIMENSIONAL SOLUTION STRUCTURE AND 13C ASSIGNMENTS OF BARSTAR USING NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY
1L1K 2002-12-04 NMR Identification and Characterization of the Flexible Regions in the 160 KD Molten Globule-like Aggregate of Barstar at Low pH
2ZA4 2008-05-20 1.58 Crystal Structural Analysis of Barnase-barstar Complex
1AY7 1999-03-02 1.7 RIBONUCLEASE SA COMPLEX WITH BARSTAR
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
1BRS 1994-06-22 2.0 PROTEIN-PROTEIN RECOGNITION: CRYSTAL STRUCTURAL ANALYSIS OF A BARNASE-BARSTAR COMPLEX AT 2.0-A RESOLUTION
2HXX 2006-08-22 2.0 Aminotryptophan Barstar
1B27 1998-12-09 2.1 STRUCTURAL RESPONSE TO MUTATION AT A PROTEIN-PROTEIN INTERFACE
1B2U 1998-12-09 2.1 STRUCTURAL RESPONSE TO MUTATION AT A PROTEIN-PROTEIN INTERFACE
1X1W 2005-04-26 2.1 Water-mediate interaction at aprotein-protein interface
3DA7 2009-04-14 2.25 A conformationally strained, circular permutant of barnase
1X1U 2005-04-26 2.3 Water-mediate interaction at aprotein-protein interface
1X1X 2005-04-26 2.3 Water-mediate interaction at aprotein-protein interface
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
1A19 1998-04-08 2.76 BARSTAR (FREE), C82A MUTANT

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
100.0 Barstar P11540 BARS_BACAM