Thermodynamics of unfolding of ribonuclease A under high pressure. A study by proton NMR.


Thermodynamic stability of ribonuclease A (6.2 mM pH 1.0, 0.15 M KCl, in 2H2O) has been studied in the pressure range of 1 to 2000 atm and in the temperature range of 7.5 to 40 degrees C with a high pressure 1H NMR technique at 400 MHz. His epsilon proton resonances were used as reporter groups to measure fractions of folded and unfolded species. Gibbs energy differences between folded and unfolded species were obtained as functions of pressure for different temperatures and as functions of temperature for different pressures. The volume increase upon unfolding, delta V, was negative and temperature-dependent, decreasing from -10 ml/mol at 7.5 degrees C to -30 ml/mol at 37 degrees C. From the least squares-fitting of experimental Gibbs energy differences to a theoretical expression holding pressure and delta Cp constant, we determined best-fit values of delta G, delta H, delta S and delta Cp for different values of pressure in the temperature range 7.5 to 40 degrees C. We found that delta Cp is dependent on pressure, decreasing from 1.79 kcal/mol K at 1 atm to 1.08 kcal/mol K at 2000 atm. These findings appear to be consistent with a notion that the state of hydration of non-polar side-chains upon unfolding of the protein is a major factor that determines the pressure dependence of the conformational stability of ribonuclease A under the chosen experimental condition. Study holds ProTherm entries: 7490 Extra Details: 1. thermodynamic parameters for other pressures are also available,2. water was added in the experiment protein unfolding; thermodynamics; high pressure; NMR;,ribonuclease A

Submission Details

ID: TqTfVohu

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:34 p.m.

Version: 1

Publication Details
Yamaguchi T;Yamada H;Akasaka K,J. Mol. Biol. (1995) Thermodynamics of unfolding of ribonuclease A under high pressure. A study by proton NMR. PMID:7623385
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 UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
100.0 Ribonuclease pancreatic P61824 RNAS1_BISBI
100.0 Ribonuclease pancreatic P61823 RNAS1_BOVIN
96.8 Ribonuclease pancreatic P67926 RNAS1_CAPHI
96.8 Ribonuclease pancreatic P67927 RNAS1_SHEEP
95.2 Ribonuclease pancreatic P00657 RNAS1_BUBBU
96.0 Ribonuclease pancreatic P07847 RNAS1_AEPME
93.5 Ribonuclease pancreatic P07848 RNAS1_EUDTH
95.2 Ribonuclease pancreatic P00660 RNAS1_CONTA
92.7 Ribonuclease pancreatic P00668 RNAS1_ANTAM
90.3 Ribonuclease pancreatic P00662 RNAS1_GIRCA
96.0 Ribonuclease pancreatic Q29606 RNAS1_ORYLE