Stabilization of a protein by guanidinium chloride.


Abstract

Guanidinium chloride is a commonly used denaturant to unfold native proteins and to determine their Gibbs free energy of stabilization, delta Gstab. Here we show that this denaturant has a dual role for the stability and the folding of the model protein ribonuclease T1. When present at low concentration (0-0.3 M), guanidinium chloride stabilizes the folded protein toward thermal and urea-induced unfolding and decreases the rate of unfolding. At high concentration the function of guanidinium chloride as a denaturant dominates and ribonuclease T1 is cooperatively unfolded. Ribonuclease T1 is also strongly stabilized by other salts, such as NaCl, at low concentrations, and the dependence of the thermal stability on salt concentration is not linear. Such a complex behavior was not found in control experiments with pancreatic ribonuclease A. The stabilization in the presence of low concentrations of guanidinium chloride originates probably from the binding of guanidinium ions to one or a few cation binding sites that exist in native ribonuclease T1. It is not observed when an additional salt, NaCl, is present simultaneously. The favorable interaction of guanidinium chloride with the native protein leads to increased values for delta Gstab, when unfolding transitions induced by guanidinium chloride are analyzed on the basis of the two-state model by the linear extrapolation procedure. The noncoincidence of these delta Gstab values with stability data derived from urea-induced or thermal unfolding transitions does not imply that the two-state model is not appropriate but that the linear extrapolation to zero molar denaturant is incorrect.(ABSTRACT TRUNCATED AT 250 WORDS) Study holds ProTherm entries: 4556, 4557 Extra Details: guanidinium chloride; cooperative; cation binding sites;,two-state model

Submission Details

ID: tFe7e5Pr3

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:26 p.m.

Version: 1

Publication Details
Mayr LM;Schmid FX,Biochemistry (1993) Stabilization of a protein by guanidinium chloride. PMID:8347603
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
1B2M 1998-11-27T00:00:00+0000 2.0 THREE-DIMENSIONAL STRUCTURE OF RIBONULCEASE T1 COMPLEXED WITH AN ISOSTERIC PHOSPHONATE ANALOGUE OF GPU: ALTERNATE SUBSTRATE BINDING MODES AND CATALYSIS.
1BIR 1996-01-04T00:00:00+0000 1.8 RIBONUCLEASE T1, PHE 100 TO ALA MUTANT COMPLEXED WITH 2' GMP
1BU4 1998-09-11T00:00:00+0000 1.9 RIBONUCLEASE 1 COMPLEX WITH 2'GMP
1BVI 1998-09-15T00:00:00+0000 1.9 RIBONUCLEASE T1 (WILDTYPE) COMPLEXED WITH 2'GMP
1CH0 1999-03-30T00:00:00+0000 2.3 RNASE T1 VARIANT WITH ALTERED GUANINE BINDING SEGMENT
1DET 1996-02-20T00:00:00+0000 1.8 RIBONUCLEASE T1 CARBOXYMETHYLATED AT GLU 58 IN COMPLEX WITH 2'GMP
1FYS 2000-10-03T00:00:00+0000 2.0 Ribonuclease T1 V16C mutant
1FZU 2000-10-04T00:00:00+0000 1.8 RNAse T1 V78A mutant
1G02 2000-10-05T00:00:00+0000 1.86 Ribonuclease T1 V16S mutant
1GSP 1997-11-28T00:00:00+0000 2.2 RIBONUCLEASE T1 COMPLEXED WITH 2',3'-CGPS, 1 DAY

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
100.0 Guanyl-specific ribonuclease T1 P00651 RNT1_ASPOR