title: Molecular dimensions and their distributions in early folding intermediates.
abstract: The integration of ultrafast mixing technology with bright X-ray sources at synchrotrons and with sophisticated fluorescence methods is yielding quantitative insights into the dimensions of unfolded proteins and transient intermediates that appear during the earliest stages of folding. Time-resolved Förster resonance energy transfer and small-angle X-ray scattering techniques, which are sensitive to the distributions of distances, can also elucidate the nature of processes otherwise obscured in measurements of a single ensemble-averaged optical property. These two approaches have recently been applied to the protein folding problem. In particular, progress has been made in characterizing the dimensions of unfolded states, and discriminating between barrierless and barrier-limited collapse of the unfolded state at the beginning of the folding reaction.
authors.affiliation: Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605, USA. osman.bilsel@umassmed.edu
authors.forename: Osman
authors.initials: O
authors.lastname: Bilsel
authors.forename: C Robert
authors.initials: CR
authors.lastname: Matthews
mesh_terms: D000818:Animals; D031541:Fluorescence Resonance Energy Transfer; D006801:Humans; D011489:Protein Denaturation; D017510:Protein Folding