title: Urea and guanidinium induced denaturation of a Trp-cage miniprotein.
abstract: Using a combination of experimental techniques (circular dichroism, differential scanning calorimetry, and NMR) and molecular dynamics simulations, we performed an extensive study of denaturation of the Trp-cage miniprotein by urea and guanidinium. The experiments, despite their different sensitivities to various aspects of the denaturation process, consistently point to simple, two-state unfolding process. Microsecond molecular dynamics simulations with a femtosecond time resolution allow us to unravel the detailed molecular mechanism of Trp-cage unfolding. The process starts with a destabilizing proline shift in the hydrophobic core of the miniprotein, followed by a gradual destruction of the hydrophobic loop and the α-helix. Despite differences in interactions of urea vs guanidinium with various peptide moieties, the overall destabilizing action of these two denaturants on Trp-cage is very similar.
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, and Center for Biomolecules and Complex Molecular Systems, Flemingovo nám. 2, 16610 Prague 6, Czech Republic.
authors.forename: Jan
authors.initials: J
authors.lastname: Heyda
authors.forename: Milan
authors.initials: M
authors.lastname: Kožíšek
authors.forename: Lucie
authors.initials: L
authors.lastname: Bednárova
authors.forename: Gary
authors.initials: G
authors.lastname: Thompson
authors.forename: Jan
authors.initials: J
authors.lastname: Konvalinka
authors.forename: Jiří
authors.initials: J
authors.lastname: Vondrášek
authors.forename: Pavel
authors.initials: P
authors.lastname: Jungwirth
mesh_terms: D002152:Calorimetry, Differential Scanning; D002942:Circular Dichroism; D019791:Guanidine / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D011489:Protein Denaturation; D014364:Tryptophan / Q000737:chemistry*; D014508:Urea / Q000737:chemistry*
chemical_list: D014364:Tryptophan; D014508:Urea; D019791:Guanidine