Charge-charge interactions influence the denatured state ensemble and contribute to protein stability.


Abstract

Several recent studies have shown that it is possible to increase protein stability by improving electrostatic interactions among charged groups on the surface of the folded protein. However, the stability increases are considerably smaller than predicted by a simple Coulomb's law calculation, and in some cases, a charge reversal on the surface leads to a decrease in stability when an increase was predicted. These results suggest that favorable charge-charge interactions are important in determining the denatured state ensemble, and that the free energy of the denatured state may be decreased more than that of the native state by reversing the charge of a side chain. We suggest that when the hydrophobic and hydrogen bonding interactions that stabilize the folded state are disrupted, the unfolded polypeptide chain rearranges to compact conformations with favorable long-range electrostatic interactions. These charge-charge interactions in the denatured state will reduce the net contribution of electrostatic interactions to protein stability and will help determine the denatured state ensemble. To support this idea, we show that the denatured state ensemble of ribonuclease Sa is considerably more compact at pH 7 where favorable charge-charge interactions are possible than at pH 3, where unfavorable electrostatic repulsion among the positive charges causes an expansion of the denatured state ensemble. Further support is provided by studies of the ionic strength dependence of the stability of charge-reversal mutants of ribonuclease Sa. These results may have important implications for the mechanism of protein folding. Study holds ProTherm entries: 8358, 8359, 8360, 8361, 8362, 8363, 8364, 8365 Extra Details: denatured states; electrostatic interactions;,pH dependence; protein folding; protein stability

Submission Details

ID: EETUZqvp

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:36 p.m.

Version: 1

Publication Details
Pace CN;Alston RW;Shaw KL,Protein Sci. (2000) Charge-charge interactions influence the denatured state ensemble and contribute to protein stability. PMID:10933506
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
1AY7 1997-11-14T00:00:00+0000 1.7 RIBONUCLEASE SA COMPLEX WITH BARSTAR
1BOX 1998-08-07T00:00:00+0000 1.6 N39S MUTANT OF RNASE SA FROM STREPTOMYCES AUREOFACIENS
1C54 1999-10-22T00:00:00+0000 0 SOLUTION STRUCTURE OF RIBONUCLEASE SA
1GMP 1992-10-01T00:00:00+0000 1.7 COMPLEX OF RIBONUCLEASE FROM STREPTOMYCES AUREOFACIENS WITH 2'-GMP AT 1.7 ANGSTROMS RESOLUTION
1GMQ 1992-10-01T00:00:00+0000 1.8 COMPLEX OF RIBONUCLEASE FROM STREPTOMYCES AUREOFACIENS WITH 2'-GMP AT 1.7 ANGSTROMS RESOLUTION
1GMR 1992-10-01T00:00:00+0000 1.77 COMPLEX OF RIBONUCLEASE FROM STREPTOMYCES AUREOFACIENS WITH 2'-GMP AT 1.7 ANGSTROMS RESOLUTION
1I70 2001-03-07T00:00:00+0000 1.7 CRYSTAL STRUCTURE OF RNASE SA Y86F MUTANT
1I8V 2001-03-16T00:00:00+0000 1.25 CRYSTAL STRUCTURE OF RNASE SA Y80F MUTANT
1LNI 2002-05-03T00:00:00+0000 1.0 CRYSTAL STRUCTURE ANALYSIS OF A RIBONUCLEASE FROM STREPTOMYCES AUREOFACIENS AT ATOMIC RESOLUTION (1.0 A)
1RGE 1995-06-05T00:00:00+0000 1.15 HYDROLASE, GUANYLORIBONUCLEASE

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
100.0 Endolysin P00720 ENLYS_BPT4
100.0 Guanyl-specific ribonuclease T1 P00651 RNT1_ASPOR
100.0 Guanyl-specific ribonuclease Sa P05798 RNSA_KITAU