SecB binds only to a late native-like intermediate in the folding pathway of barstar and not to the unfolded state

Panse, Vikram G and Udgaonkar, Jayant B and Varadarajan, Raghavan (1998) SecB binds only to a late native-like intermediate in the folding pathway of barstar and not to the unfolded state. In: Biochemistry, 37 (41). pp. 14477-14483.

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Abstract

SecB is a cytosolic, tetrameric chaperone of Escherichia coli which maintains precursor proteins in a translocation competent state. We have investigated the effect of SecB on the refolding kinetics of the small protein barstar in I M guanidine hydrochloride at pH 7.0 and 25 degrees C using fluorescence spectroscopy. We show that SecB does not bind either the native or the unfolded states of barstar but binds to a late near-native intermediate along the folding pathway. For barstar, polypeptide collapse and formation of a hydrophobic surface are required for binding to SecB. SecB does not change the apparent rate constant of barstar refolding. The kinetic data for SecB binding to barstar are not consistent with simple kinetic partitioning models.

Item Type:	Journal Article
Publication:	Biochemistry
Publisher:	American Chemical Society
Additional Information:	Copyright of this article belongs to American Chemical Society.
Department/Centre:	Division of Biological Sciences > Molecular Biophysics Unit
Date Deposited:	11 Dec 2009 08:06
Last Modified:	19 Sep 2010 05:27
URI:	http://eprints.iisc.ac.in/id/eprint/19218

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