The single helix in protein L is largely disrupted at the rate-limiting step in folding

TitleThe single helix in protein L is largely disrupted at the rate-limiting step in folding
Publication TypeJournal Article
Year of Publication1998
AuthorsKim, D. E., Yi Q., Gladwin S. T., Goldberg J. M., & Baker D.
JournalJournal of molecular biology
Volume284
Issue3
Pagination807-15
Date Published1998 Dec 4
ISSN0022-2836
KeywordsBacterial Proteins, DNA-Binding Proteins, Kinetics, Primary Publication, Protein Folding, Proteins, Thermodynamics
Abstract

To investigate the role of helix formation in the folding of protein L, a 62 residue alpha/beta protein, we studied the consequences of both single and multiple mutations in the helix on the kinetics of folding. A triple mutant with 11 additional carbon atoms in core residues in the amino-terminal portion of the helix folded substantially faster than wild type, suggesting that hydrophobic association with residues elsewhere in the protein occurs at the rate-limiting step in folding. However, helix-destabilizing mutations had little effect on the rate of folding; in particular, a triple glycine substitution on the solvent-exposed side of the helix increased the unfolding rate 56-fold while reducing the folding rate less than threefold. Thus, in contrast to the predictions of models of folding involving the coalescence of well-formed secondary structure elements, the single helix in protein L appears to be largely disrupted at the rate-limiting step in folding and unfolding.

Alternate JournalJ. Mol. Biol.
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