Protein stabilization by removal of unsatisfied polar groups: computational approaches and experimental tests.


Abstract

The role of polar and charged side chains in partially buried protein environments has been probed in a variant of Arc repressor (MYL) in which hydrophobic interactions between Met31, Tyr36, and Leu40 replace the wild-type salt-bridge interactions between Arg31, Glu36, and Arg40. In the absence of this salt-bridge triad, three additional side chains were identified by continuum electrostatic calculations as incurring larger desolvation penalties during folding than were recovered in favorable electrostatic interactions in the folded state. These side chains (Asn29, Ser44, and Glu48) were mutated singly and collectively to alanine in the MYL background, and the thermodynamic stabilities of the resulting mutant proteins were found to be increased by 0.1 to 1.3 kcal/mol of dimer. All of the mutants displayed cooperative thermal melts and appeared to have well-packed hydrophobic cores by near-UV circular dichroism spectroscopy, indicating that conformational specificity is maintained. The Arc variant (MYL-NA29/SA44/EA48) in which the entire six-residue polar network is replaced by nonpolar groups is 5.1 kcal/mol of dimer more stable than wild type, indicating that the strategy of replacing buried or partially buried charged and polar side chains with hydrophobic residues can lead to substantial stabilization. Study holds ProTherm entries: 2520, 2521, 2522, 2523, 2524, 11811, 11812, 11813, 11814, 11815 Extra Details: variant of Arc repressor (MYL; R31M,E36Y,R40L) Arc repressor; hydrophobic interactions; salt-bridge; electrostatic;,protein stabilization; polar groups; conformational specificity

Submission Details

ID: fDGTgHiJ3

Submitter: Connie Wang

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

Version: 1

Publication Details
Hendsch ZS;Jonsson T;Sauer RT;Tidor B,Biochemistry (1996) Protein stabilization by removal of unsatisfied polar groups: computational approaches and experimental tests. PMID:8672461
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
1ARQ 1994-01-31 RELAXATION MATRIX REFINEMENT OF THE SOLUTION STRUCTURE OF THE ARC REPRESSOR
1ARR 1994-01-31 RELAXATION MATRIX REFINEMENT OF THE SOLUTION STRUCTURE OF THE ARC REPRESSOR
1B28 1999-11-03 ARC REPRESSOR MYL MUTANT FROM SALMONELLA BACTERIOPHAGE P22
1QTG 1999-07-12 AVERAGED NMR MODEL OF SWITCH ARC, A DOUBLE MUTANT OF ARC REPRESSOR
1NLA 2003-03-18 Solution Structure of Switch Arc, a Mutant with 3(10) Helices Replacing a Wild-Type Beta-Ribbon
1BAZ 1998-06-17 1.9 ARC REPRESSOR MUTANT PHE10VAL
1U9P 2005-02-15 1.9 Permuted single-chain Arc
1MYL 1995-01-26 2.4 SUBSTITUTING HYDROPHOBIC RESIDUES FOR A BURIED SALT BRIDGE ENHANCES PROTEIN STABILITY BUT DOES NOT REDUCE CONFORMATIONAL SPECIFICITY
1MYK 1995-01-26 2.4 CRYSTAL STRUCTURE, FOLDING, AND OPERATOR BINDING OF THE HYPERSTABLE ARC REPRESSOR MUTANT PL8
1BDT 1999-02-16 2.5 WILD TYPE GENE-REGULATING PROTEIN ARC/DNA COMPLEX
1PAR 1994-07-31 2.6 DNA RECOGNITION BY BETA-SHEETS IN THE ARC REPRESSOR-OPERATOR CRYSTAL STRUCTURE
1BDV 1999-01-06 2.8 ARC FV10 COCRYSTAL

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
100.0 Transcriptional repressor arc P03050 RARC_BPP22