1UGX

Crystal structure of jacalin- Me-alpha-T-antigen (Gal-beta(1-3)-GalNAc-alpha-o-Me) complex

Summary for 1UGX

• Entry DOI: 10.2210/pdb1ugx/pdb
• Related: 1JAC 1M26 1UGW 1UGY 1UH0 1UH1
• Descriptor: Agglutinin alpha chain, Agglutinin beta-3 chain, beta-D-galactopyranose-(1-3)-methyl 2-acetamido-2-deoxy-alpha-D-galactopyranoside, ... (4 entities in total)
• Functional Keywords: all beta sheet protein, beta-prism i fold, galactose-specific, sugar binding protein
• Biological source: Artocarpus integer; More
• Total number of polymer chains: 2
• Total formula weight: 17100.06

Authors

Jeyaprakash, A.A.,Katiyar, S.,Swaminathan, C.P.,Sekar, K.,Surolia, A.,Vijayan, M. (deposition date: 2003-06-22, release date: 2003-09-23, Last modification date: 2023-12-27)

Primary citation

Jeyaprakash, A.A.,Katiyar, S.,Swaminathan, C.P.,Sekar, K.,Surolia, A.,Vijayan, M.
Structural Basis of the Carbohydrate Specificities of Jacalin: An X-ray and Modeling Study
J.MOL.BIOL., 332:217-228, 2003

PubMed Abstract: The structures of the complexes of tetrameric jacalin with Gal, Me-alpha-GalNAc, Me-alpha-T-antigen, GalNAcbeta1-3Gal-alpha-O-Me and Galalpha1-6Glc (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 alpha-substituents, when present, interact, primarily hydrophobically, with secondary site A which has variable geometry. O-H..., centered pi and C-H...pi hydrogen bonds involving this site also exist. On the other hand, beta-substitution leads to severe steric clashes. Therefore, in complexes involving beta-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.

PubMed: 12946359
DOI: 10.1016/S0022-2836(03)00901-X

Experimental method

X-RAY DIFFRACTION (1.6 Å)