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The effects of disulfide bonds on the denatured state of barnase
Author(s) -
Clarke Jane,
Hounslow Andrea M.,
Fersht Alan R.,
Bond Chris J.,
Daggett Valerie
Publication year - 2000
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1110/ps.9.12.2394
Subject(s) - barnase , disulfide bond , chemistry , protein disulfide isomerase , crystallography , biophysics , stereochemistry , biochemistry , biology , ribonuclease , rna , gene
The effects of engineered disulfide bonds on protein stability are poorly understood because they can influence the structure, dynamics, and energetics of both the native and denatured states. To explore the effects of two engineered disulfide bonds on the stability of barnase, we have conducted a combined molecular dynamics and NMR study of the denatured state of the two mutants. As expected, the disulfide bonds constrain the denatured state. However, specific extended β‐sheet structure can also be detected in one of the mutant proteins. This mutant is also more stable than would be predicted. Our study suggests a possible cause of the very high stability conferred by this disulfide bond: the wild‐type denatured ensemble is stabilized by a nonnative hydrophobic cluster, which is constrained from occurring in the mutant due to the formation of secondary structure.