Determination of intramolecular distance distribution during protein folding on the millisecond timescale

Department of Life Sciences, Bar Ilan University, Ramat-Gan, 52900, Israel.
Journal of Molecular Biology (Impact Factor: 3.96). 07/2000; 299(5):1363-71. DOI: 10.1006/jmbi.2000.3814
Source: PubMed

ABSTRACT A method for determination of transient (on the millisecond timescale) intramolecular distance distributions (IDDs) by time-resolved dynamic non-radiative excitation energy transfer measurements was developed. The time-course of the development of the IDD between residues 73 and 203 in the CORE domain of Escherichia coli adenylate kinase throughout refolding from the GuHCl-induced denatured state was determined. The mean of the apparent IDD reduced to a value close to its magnitude in the native protein, within 2 ms (the dead-time of the instrument). At that time the width of that distribution was rather large (16+/-2 A). The large width implies that the intramolecular diffusion coefficient of the labeled segment does not exceed 10(-7) cm(2)/second. In a second slower phase of the refolding transition, the width was reduced to its native value (6+/-4 A).

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