Title
Microsecond hydrophobic collapse in the folding of Escherichia coli dihydrofolate reductase, an alpha/beta-type protein
GSBS Program
Biochemistry & Molecular Pharmacology
UMMS Affiliation
Graduate School of Biomedical Sciences; Department of Biochemistry and Molecular Pharmacology
Date
3-3-2007
Document Type
Article
Medical Subject Headings
Enzyme Stability; Escherichia coli; *Hydrophobicity; Models, Molecular; Protein Denaturation; *Protein Folding; Protein Renaturation; Protein Structure, Secondary; Scattering, Small Angle; Tetrahydrofolate Dehydrogenase
Disciplines
Life Sciences | Medicine and Health Sciences
Abstract
Using small-angle X-ray scattering combined with a continuous-flow mixing device, we monitored the microsecond compaction dynamics in the folding of Escherichia coli dihydrofolate reductase, an alpha/beta-type protein. A significant collapse of the radius of gyration from 30 A to 23.2 A occurs within 300 micros after the initiation of refolding by a urea dilution jump. The subsequent folding after the major chain collapse occurs on a considerably longer time-scale. The protein folding trajectories constructed by comparing the development of the compactness and the secondary structure suggest that the specific hydrophobic collapse model rather than the framework model better explains the experimental observations. The folding trajectory of this alpha/beta-type protein is located between those of alpha-helical and beta-sheet proteins, suggesting that native structure determines the folding landscape.
Rights and Permissions
Citation: J Mol Biol. 2007 Apr 20;368(1):219-29. Epub 2007 Feb 7. Link to article on publisher's site