Native topology or specific interactions: What is more important for protein folding?

TitleNative topology or specific interactions: What is more important for protein folding?
Publication TypeJournal Article
Year of Publication2001
AuthorsFerrara P., Caflisch A.
JournalJournal of Molecular Biology
Date Published2001 Mar 2
Type of ArticleResearch Article
KeywordsComputer Simulation, Hydrogen Bonding, Kinetics, Models, Molecular, Nuclear Magnetic Resonance, Biomolecular, Peptides, Protein Denaturation, Protein Folding, Protein Structure, Secondary, Thermodynamics

Fifty-five molecular dynamics runs of two three-stranded antiparallel β-sheet peptides were performed to investigate the relative importance of amino acid sequence and native topology. The two peptides consist of 20 residues each and have a sequence identity of 15 %. One peptide has Gly-Ser (GS) at both turns, while the other has d-Pro-Gly ((D)PG). The simulations successfully reproduce the NMR solution conformations, irrespective of the starting structure. The large number of folding events sampled along the trajectories at 360 K (total simulation time of about 5 micros) yield a projection of the free-energy landscape onto two significant progress variables. The two peptides have compact denatured states, similar free-energy surfaces, and folding pathways that involve the formation of a β-hairpin followed by consolidation of the unstructured strand. For the GS peptide, there are 33 folding events that start by the formation of the 2-3 β-hairpin and 17 with first the 1-2 β-hairpin. For the (D)PG peptide, the statistical predominance is opposite, 16 and 47 folding events start from the 2-3 β-hairpin and the 1-2 β-hairpin, respectively. These simulation results indicate that the overall shape of the free-energy surface is defined primarily by the native-state topology, in agreement with an ever-increasing amount of experimental and theoretical evidence, while the amino acid sequence determines the statistically predominant order of the events.



Alternate JournalJ. Mol. Biol.
PubMed ID11243792
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