Transition States in Protein Folding Kinetics: The Structural Interpretation of Phi-values

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dc.creatorWeikl, Thomas R.
dc.creatorDill, Ken A.
dc.date2006-05-30
dc.date.accessioned2026-07-07T07:15:14Z
dc.date.available2026-07-07T07:15:14Z
dc.descriptionPhi-values are experimental measures of the effects of mutations on the folding kinetics of a protein. A central question is which structural information Phi-values contain about the transition state of folding. Traditionally, a Phi-value is interpreted as the 'nativeness' of a mutated residue in the transition state. However, this interpretation is often problematic because it assumes a linear relation between the nativeness of the residue and its free-energy contribution. We present here a better structural interpretation of Phi-values for mutations within a given helix. Our interpretation is based on a simple physical model that distinguishes between secondary and tertiary free-energy contributions of helical residues. From a linear fit of our model to the experimental data, we obtain two structural parameters: the extent of helix formation in the transition state, and the nativeness of tertiary interactions in the transition state. We apply our model to all proteins with well-characterized helices for which more than 10 Phi-values are available: protein A, CI2, and protein L. The model captures nonclassical Phi-values <0 or >1 in these helices, and explains how different mutations at a given site can lead to different Phi-values.
dc.description26 pages, 7 figures, 5 tables
dc.identifierhttps://arxiv.org/abs/q-bio/0605048
dc.identifierhttp://arxiv.org/abs/q-bio/0605048
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/113188
dc.subjectBiomolecules
dc.titleTransition States in Protein Folding Kinetics: The Structural Interpretation of Phi-values
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