title: Conformational properties of unfolded HypF-N.
abstract: We have measured the intramolecular diffusion rate between distant residues in the aggregation-prone protein HypF-N under various denaturing conditions. Using the method of cysteine quenching of the tryptophan triplet state, we find that intramolecular diffusion remains roughly constant at high concentrations of denaturant (2-6 M GdnHCl) and slows down at low concentrations of denaturant, but the decrease is not uniform throughout the chain. Extrapolation of these measurements to 0 M GdnHCl gives D approximately 10(-7) cm(2) s(-1), about 1 order of magnitude lower than unstructured peptides and at least 2 orders of magnitude higher than well-behaved proteins. This suggests that there is a dynamic range of conformational reorganization within which partially unfolded states are prone to aggregation.
authors.affiliation: Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA.
authors.forename: Yujie
authors.initials: Y
authors.lastname: Chen
authors.forename: Claudia
authors.initials: C
authors.lastname: Parrini
authors.forename: Niccolò
authors.initials: N
authors.lastname: Taddei
authors.forename: Lisa J
authors.initials: LJ
authors.lastname: Lapidus
mesh_terms: D019878:Carboxyl and Carbamoyl Transferases / Q000737:chemistry* / Q000235:genetics; D003545:Cysteine / Q000737:chemistry; D004058:Diffusion; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics; D019791:Guanidine / Q000737:chemistry; D007700:Kinetics; D009154:Mutation; D011487:Protein Conformation; D011489:Protein Denaturation; D017510:Protein Folding; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics; D014364:Tryptophan / Q000737:chemistry
chemical_list: D029968:Escherichia coli Proteins; D011994:Recombinant Proteins; D014364:Tryptophan; D019878:Carboxyl and Carbamoyl Transferases; C504838:hypF protein, E coli; D019791:Guanidine; D003545:Cysteine