1PXD

Crystal structure of the complex of jacalin with meso-tetrasulphonatophenylporphyrin.

Summary for 1PXD

• Entry DOI: 10.2210/pdb1pxd/pdb
• Related: 1JN2
• Descriptor: Agglutinin alpha chain, Agglutinin beta-3 chain, 5,10,15,20-TETRAKIS(4-SULPFONATOPHENYL)-21H,23H-PORPHINE, ... (4 entities in total)
• Functional Keywords: lectin, porphyrin, sugar binding protein
• Biological source: Artocarpus integer; More
• Total number of polymer chains: 2
• Total formula weight: 18610.78

Authors

Goel, M.,Anuradha, P.,Kaur, K.J.,Maiya, B.G.,Swamy, M.J.,Salunke, D.M. (deposition date: 2003-07-03, release date: 2004-02-03, Last modification date: 2023-08-16)

Primary citation

Goel, M.,Anuradha, P.,Kaur, K.J.,Maiya, B.G.,Swamy, M.J.,Salunke, D.M.
Porphyrin binding to jacalin is facilitated by the inherent plasticity of the carbohydrate-binding site: novel mode of lectin-ligand interaction.
Acta Crystallogr.,Sect.D, 60:281-288, 2004

PubMed Abstract: The crystal structure of the complex of meso-tetrasulfonatophenylporphyrin (H(2)TPPS) with jack fruit (Artocarpus integriflora) agglutinin (jacalin) has been determined at 1.8 A resolution. A porphyrin pair is sandwiched between two symmetry-related jacalin monomers in the crystal, leading to a cross-linking network of protein molecules. Apart from the stacking interactions, H(2)TPPS also forms hydrogen bonds, some involving water bridges, with jacalin at the carbohydrate-binding site. The residues that are involved in rendering galactopyranoside specificity to jacalin undergo conformational adjustments in order to accommodate the H(2)TPPS molecule. The water molecules at the carbohydrate-binding site of jacalin cement the jacalin-porphyrin interactions, optimizing their complementarity. Interactions of porphyrin with jacalin are relatively weak compared with those observed between galactopyranoside and jacalin, perhaps because the former largely involves water-mediated hydrogen bonds. While H(2)TPPS binds to jacalin at the carbohydrate-binding site as in the case of ConA, its mode of interaction with jacalin is very different. H(2)TPPS does not enter the carbohydrate-binding cavity of jacalin. Instead, it sits over the binding site. While the porphyrin binding is mediated by replicating the hydrogen-bonding network of mannopyranoside through the sulfonate atoms in the case of ConA, the plasticity associated with the carbohydrate-binding site accommodates the pluripotent porphyrin molecule in the case of jacalin through an entirely different set of interactions.

PubMed: 14747704
DOI: 10.1107/S0907444903026684

Experimental method

X-RAY DIFFRACTION (1.8 Å)