FCCC LOGO Faculty Publications
Khorasanizadeh S , Peters ID , Roder H
Evidence for a three-state model of protein folding from kinetic analysis of ubiquitin variants with altered core residues
Nature Structural Biology. 1996 Feb;3(2) :193-205
PMID: ISI:A1996TT67400018   
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Abstract
To elucidate the kinetic importance of structural intermediates in single-domain proteins, we measured the effect of solution conditions and amino-acid changes at a central core residue of ubiquitin (Val 26) on the kinetics of folding and unfolding. Kinetic analysis in terms of a sequential three-state mechanism provides insight into the contribution of specific interactions within the ubiquitin core to the structural stability of the native and intermediate states. The observation that disruptive mutations and/or addition of denaturants result in an apparent two-state folding process with slower rates is explained by the destabilization of a partially folded intermediate, which is in rapid equilibrium with unfolded states. The model predicts that under sufficiently stabilizing conditions kinetic intermediates may become populated even for proteins showing apparent two- state kinetics.
Notes
Times Cited: 143 English Article TT674 NATURE STRUCT BIOLOGY