The effect of pH on the unfolding pathway and stability of ribosome-inactivating protein abrin-II

Krupakar, Jayarapu and Das, Puspendu K and Podder, Sunil K (1998) The effect of pH on the unfolding pathway and stability of ribosome-inactivating protein abrin-II. In: Biochemistry and Molecular Biology International, 46 (02). pp. 415-424.

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Abstract

The effect of pH on the unfolding pathway acid the stability of the toxic protein abrin-II have been studied by increasing denaturant concentrations of guanidine hydrochloride and by monitoring the change in 8,1-anilino naphthalene sulfonic acid (ANS) fluorescence upon binding to the hydrophobic sites of the protein. Intrinsic protein fluorescence, far and near UV-circular dichroism (CD) spectroscopy and ANS binding studies reveal that the unfolding of abrin-II occurs through two intermediates at pH 7.2 and one intermediate at pH 4.5. At pH 7.2, the two subunits A and B of abrin-II unfold sequentially. The native protein is more stable at pH 4.5 than at pH 7.2. However, the stability of the abrin-II A-subunit is not affected by a change in pH. These observations may assist in an understanding of the physiologically relevant transmembrane translocation of the toxin.

Item Type:	Journal Article
Publication:	Biochemistry and Molecular Biology International
Publisher:	Academic Press
Additional Information:	Copyright of this article belongs to Academic Press.
Keywords:	ribosome-inactivating protein, abrin-II;pH;stability, unfolding;guanidine hydrochloride;fluorescence, circular dichroism, 8,1-anilino naphthalene sulfonic acid, lactose.
Department/Centre:	Division of Biological Sciences > Biochemistry Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	02 Jun 2009 06:40
Last Modified:	19 Sep 2010 05:28
URI:	http://eprints.iisc.ac.in/id/eprint/19404

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