Prediction of protein-folding mechanisms from free-energy landscapes derived from native structures

TitlePrediction of protein-folding mechanisms from free-energy landscapes derived from native structures
Publication TypeJournal Article
Year of Publication1999
AuthorsAlm, E., & Baker D.
JournalProceedings of the National Academy of Sciences of the United States of America
Volume96
Issue20
Pagination11305-10
Date Published1999 Sep 28
ISSN0027-8424
KeywordsModels, Theoretical, Primary Publication, Protein Conformation, Protein Folding, Thermodynamics
Abstract

Guided by recent experimental results suggesting that protein-folding rates and mechanisms are determined largely by native-state topology, we develop a simple model for protein folding free-energy landscapes based on native-state structures. The configurations considered by the model contain one or two contiguous stretches of residues ordered as in the native structure with all other residues completely disordered; the free energy of each configuration is the difference between the entropic cost of ordering the residues, which depends on the total number of residues ordered and the length of the loop between the two ordered segments, and the favorable attractive interactions, which are taken to be proportional to the total surface area buried by the ordered residues in the native structure. Folding kinetics are modeled by allowing only one residue to become ordered/disordered at a time, and a rigorous and exact method is used to identify free-energy maxima on the lowest free-energy paths connecting the fully disordered and fully ordered configurations. The distribution of structure in these free-energy maxima, which comprise the transition-state ensemble in the model, are reasonably consistent with experimental data on the folding transition state for five of seven proteins studied. Thus, the model appears to capture, at least in part, the basic physics underlying protein folding and the aspects of native-state topology that determine protein-folding mechanisms.

Alternate JournalProc. Natl. Acad. Sci. U.S.A.
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