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

Krupakar, Jayarapu ; Das, Puspendu K. ; Podder, Sunil K. (1998) The effect of pH on the unfolding pathway and stability of ribosome-inactivating protein abrin-II IUBMB Life, 46 (2). pp. 415-424. ISSN 1521-6543

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Official URL: http://onlinelibrary.wiley.com/doi/10.1080/1521654...

Related URL: http://dx.doi.org/10.1080/15216549800203932

Abstract

The effect of pH on the unfolding pathway and 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:Article
Source:Copyright of this article belongs to International Union of Biochemistry and Molecular Biology.
Keywords:Ribosome-inactivating Protein; Abrin-II; pH; Stability; Unfolding; Guanidine Hydrochloride; Fluorescence; Circular Dichroism; 8,1-anilino Naphthalene Sulfonic Acid; Lactose
ID Code:10109
Deposited On:02 Nov 2010 09:57
Last Modified:16 May 2016 19:47

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