Structural characterization of protein-denaturant interactions: crystal structures of hen egg-white lysozyme in complex with DMSO and guanidinium chloride.

Mande, S C and Sobhia, M E (2000) Structural characterization of protein-denaturant interactions: crystal structures of hen egg-white lysozyme in complex with DMSO and guanidinium chloride. Protein engineering, 13 (2). pp. 133-41. ISSN 0269-2139

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Abstract

A variety of physico-chemical methods employ chemical denaturants to unfold proteins, and study different biophysical processes involved therein. Chemical denaturants are believed to induce unfolding by stabilizing the unfolded state of proteins over the folded state, either macroscopically or through specific interactions. In order to characterize the nature of specific interactions between proteins and denaturants, we have solved crystal structures of hen egg-white lysozyme complexed with denaturants, and report here dimethyl sulfoxide and guanidinium chloride complexes. The dimethyl sulfoxide molecules and guanidinium ions were seen to bind the protein at specific sites and were involved in characteristic interactions. They share a major binding site between them, the C site in the sugar binding cleft of the enzyme. Although the overall conformations of the complexes were very similar to the native structure, spectacular conformational changes were seen to occur locally. Temperature factors were also seen to drop dramatically in the local regions close to the denaturant binding sites. An interesting observation of the present study was the generation of a sodium ion binding site in hen egg-white lysozyme in the presence of denaturants, which was hitherto unknown in any of the other lysozyme structures solved so far. Loss of some of the crucial side chain-main chain interactions may form the initial events in lysozyme unfolding.

Item Type: Article
Additional Information: Copyright of this article belongs to OUP
Subjects: Q Science > QR Microbiology
Depositing User: Dr. K.P.S.Sengar
Date Deposited: 03 Jan 2012 16:27
Last Modified: 03 Jan 2012 16:27
URI: http://crdd.osdd.net/open/id/eprint/327

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