Structural Basis of the Carbohydrate Specificities of Jacalin: An X-ray and Modeling Study

Jeyaprakash, Arockia A and Katiyar, S and Swaminathan, CP and Sekar, K and Surolia, A and Vijayan, M (2003) Structural Basis of the Carbohydrate Specificities of Jacalin: An X-ray and Modeling Study. In: Journal of Molecular Biology, 332 (1). pp. 217-228.

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Abstract

The structures of the complexes of tetrameric jacalin with Gal, Me-a-Gal-NAc, Me-a-T-antigen, GalNAcb1-3Gal-a-O-Me and Gala1-6Glc (mellibiose) show that the sugar-binding site of jacalin has three components:the primary site, secondary site A, and secondary site B. In these structures and in the two structures reported earlier, Gal or GalNAc occupy the primary site with the anomeric carbon pointing towards secondary site A. The a-substituents, when present, interact, primarily hydrophobically, with secondary site A which has variable geometry. O–H· · ·p and C–H· · ·p hydrogen bonds involving this site also exist. On the other hand, b-substitution leads to severe steric clashes. Therefore, in complexes involving b-linked disaccharides, the reducing sugar binds at the primary site with the non-reducing end located at secondary site B. The interactions at secondary site B are primarily through water bridges. Thus, the nature of the linkage determines the mode of the association of the sugar with jacalin. The interactions observed in the crystal structures and modeling based on them provide a satisfactory qualitative explanation of the available thermodynamic data on jacalin–carbohydrate interactions. They also lead to fresh insights into the nature of the binding of glycoproteins by jacalin.

Item Type:	Journal Article
Publication:	Journal of Molecular Biology
Publisher:	Elsevier
Additional Information:	The copyright belongs to Elsevier.
Keywords:	moraceae lectin;carbohydrate specificity;jacalin carbohydrate interactions;water bridges;glycoproteins
Department/Centre:	Division of Biological Sciences > Molecular Biophysics Unit Division of Information Sciences (Doesn't exist now) > BioInformatics Centre
Date Deposited:	24 Oct 2004
Last Modified:	19 Sep 2010 04:16
URI:	http://eprints.iisc.ac.in/id/eprint/2147

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