Surface electrostatic interactions contribute little of stability of barnase.


Abstract

Electrostatic interactions are believed to play an important role in stabilizing the native structure of proteins. We have quantified the contribution to stability of an interaction between two oppositely charged side-chains on the surface of barnase. Using site-directed mutagenesis, glutamate 28 and lysine 32 were introduced onto the solvent-accessible side of the second alpha-helix in barnase. These two residues are separated by one turn of the helix, and so are ideally situated for their opposite charges to interact. Double mutant cycle analysis reveals that the interaction between Glu28 and Lys32 contributes only approximately 0.2 kcal/mol to stability of the protein. All other interactions between exposed charged side-chains in barnase examined so far also contribute little to stability. We explain this low value by their location on the surface, rather than in the interior, of the protein. Study holds ProTherm entries: 190 Extra Details: protein stability; protein folding; electrostatics; salt bridges

Submission Details

ID: xjHfKobL4

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:14 p.m.

Version: 1

Publication Details
Sali D;Bycroft M;Fersht AR,J. Mol. Biol. (1991) Surface electrostatic interactions contribute little of stability of barnase. PMID:1870131
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