Thermodynamic characterization of the conformational stability of the homodimeric protein, pea lectin

Nisar Ahmad, * and Srinivas, VR and BhanuprakashReddy, G and Surolia, Avadhesha (1998) Thermodynamic characterization of the conformational stability of the homodimeric protein, pea lectin. In: Biochemistry, 37 (47). pp. 16765-16772.

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Abstract

The conformational stability of the homodimeric pea lectin was determined by both isothermal urea-induced and thermal denaturation in the absence and presence of urea. The denaturation profiles were analyzed to obtain the thermodynamic parameters associated with the unfolding of the protein. The data not only conform to the simple A(2) double left right arrow 2U model of unfolding but also are well described by the linear extrapolation model for the nature of denaturant-protein interactions. In addition, both the conformational stability (Delta G(s)) and the Delta C-p for the protein unfolding is quite high, at about 18.79 kcal/ mol and 5.32 kcal/(mol K), respectively, which may be a reflection of the relatively larger size of the dimeric molecule (M-r 49 000) and, perhaps, a consequent larger buried hydrophobic core in the folded protein. The simple two-state (A(2) double left right arrow 2U) nature of the unfolding process, with the absence of any monomeric intermediate, suggests that the quaternary interactions alone may contribute significantly to the conformational stability of the oligomer-a point that may be general to many oligomeric proteins.

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:	17 Dec 2009 11:12
Last Modified:	19 Sep 2010 05:28
URI:	http://eprints.iisc.ac.in/id/eprint/19417

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