title: A driving force for polypeptide and protein collapse.
abstract: Experimental measurements and computational results have shown that polypeptide chains, made up of 15-25 glycine residues, collapse to compact structures in water at room temperature. This contrasts with the classic idea that the burial of nonpolar side chains, i.e., the hydrophobic effect, is the driving force of collapse and folding of polypeptides and proteins. It is thus necessary to find a different driving force for polyglycine collapse. The present study aims at showing that the hydrophobic effect has to be re-defined in terms of decrease in solvent-excluded volume associated with chain collapse so that it is characterized by a gain in translational entropy of water molecules. This indicates that the presence of nonpolar side chains is not so important for polypeptide and protein collapse, even though it may be fundamental for the attainment of a unique folded structure.
authors.affiliation: Dipartimento di Scienze Chimiche, Università degli Studi di Napoli Federico II, Complesso Universitario di Monte Sant'Angelo, Via Cintia, 80126 Napoli, Italy.
authors.forename: Antonello
authors.identifier: http://orcid.org/0000-0002-1045-7720
authors.initials: A
authors.lastname: Merlino
authors.affiliation: Dipartimento di Scienze Chimiche, Università degli Studi di Napoli Federico II, Complesso Universitario di Monte Sant'Angelo, Via Cintia, 80126 Napoli, Italy.
authors.forename: Nicola
authors.initials: N
authors.lastname: Pontillo
authors.affiliation: Dipartimento di Scienze e Tecnologie, Università del Sannio, Via Port'Arsa 11, 82100 Benevento, Italy. graziano@unisannio.it.
authors.forename: Giuseppe
authors.identifier: http://orcid.org/0000-0001-6935-8172
authors.initials: G
authors.lastname: Graziano
mesh_terms: D019277:Entropy; D057927:Hydrophobic and Hydrophilic Interactions; D055595:Mechanical Phenomena; D010455:Peptides / Q000737:chemistry* / Q000378:metabolism; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism; D012997:Solvents / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
chemical_list: D010455:Peptides; D011506:Proteins; D012997:Solvents; D014867:Water