Thermal unfolding of ribonuclease A in phosphate at neutral pH: deviations from the two-state model.


Abstract

The thermal denaturation of ribonuclease A (RNase A) in the presence of phosphate at neutral pH was studied by differential scanning calorimetry (DSC) and a combination of optical spectroscopic techniques to probe the existence of intermediate states. Fourier transform infrared (FTIR) spectra of the amide I' band and far-uv circular dichroism (CD) spectra were used to monitor changes in the secondary structure. Changes in the tertiary structure were monitored by near-uv CD. Spectral bandshape changes with change in temperature were analyzed using factor analysis. The global unfolding curves obtained from DSC confirmed that structural changes occur in the molecule before the main thermal denaturation transition. The analysis of the far-uv CD and FTIR spectra showed that these lower temperature-induced modifications occur in the secondary structure. No pretransition changes in the tertiary structure (near-uv CD) were observed. The initial changes observed in far-uv CD were attributed to the fraying of the helical segments, which would explain the loss of spectral intensity with almost no modification of spectral bandshape. Separate analyses of different regions of the FTIR amide I' band indicate that, in addition to alpha-helix, part of the pretransitional change also occurs in the beta-strands. Study holds ProTherm entries: 11364 Extra Details: Ribonuclease A; protein thermal unfolding; circular dichroism;,infrared; differential scanning calorimetry; bandshape analysis

Submission Details

ID: t8jmAYwB3

Submitter: Connie Wang

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

Version: 1

Publication Details
Stelea SD;Pancoska P;Benight AS;Keiderling TA,Protein Sci. (2001) Thermal unfolding of ribonuclease A in phosphate at neutral pH: deviations from the two-state model. PMID:11316877
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
6QMN 2019-02-07T00:00:00+0000 2.31 Crystal structure of a Ribonuclease A-Onconase chimera
1A2W 1998-01-12T00:00:00+0000 2.1 CRYSTAL STRUCTURE OF A 3D DOMAIN-SWAPPED DIMER OF BOVINE PANCREATIC RIBONUCLEASE A
1A5P 1998-02-17T00:00:00+0000 1.6 C[40,95]A VARIANT OF BOVINE PANCREATIC RIBONUCLEASE A
1A5Q 1998-02-17T00:00:00+0000 2.3 P93A VARIANT OF BOVINE PANCREATIC RIBONUCLEASE A
1AFK 1997-03-08T00:00:00+0000 1.7 CRYSTAL STRUCTURE OF RIBONUCLEASE A IN COMPLEX WITH 5'-DIPHOSPHOADENOSINE-3'-PHOSPHATE
1AFL 1997-03-08T00:00:00+0000 1.7 RIBONUCLEASE A IN COMPLEX WITH 5'-DIPHOSPHOADENOSINE 2'-PHOSPHATE AT 1.7 ANGSTROM RESOLUTION
1AFU 1997-03-14T00:00:00+0000 2.0 STRUCTURE OF RIBONUCLEASE A AT 2.0 ANGSTROMS FROM MONOCLINIC CRYSTALS
1AQP 1997-07-31T00:00:00+0000 2.0 RIBONUCLEASE A COPPER COMPLEX
1B6V 1999-01-18T00:00:00+0000 2.0 CRYSTAL STRUCTURE OF A HYBRID BETWEEN RIBONUCLEASE A AND BOVINE SEMINAL RIBONUCLEASE
1BEL 1995-12-21T00:00:00+0000 1.6 HYDROLASE PHOSPHORIC DIESTER, RNA

Relevant UniProtKB Entries

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