1J4T

Structure of Artocarpin: a Lectin with Mannose Specificity (Form 2)

Summary for 1J4T

• Entry DOI: 10.2210/pdb1j4t/pdb
• Related: 1J4S 1J4U 1JAC
• Descriptor: Artocarpin (2 entities in total)
• Functional Keywords: all beta, greek key motif, beta prism i fold, plant protein
• Biological source: Artocarpus integer
• Total number of polymer chains: 8
• Total formula weight: 128935.82

Authors

Pratap, J.V.,Jeyaprakash, A.A.,Rani, P.G.,Sekar, K.,Surolia, A.,Vijayan, M. (deposition date: 2001-10-30, release date: 2002-03-27, Last modification date: 2023-12-27)

Primary citation

Pratap, J.V.,Jeyaprakash, A.A.,Rani, P.G.,Sekar, K.,Surolia, A.,Vijayan, M.
Crystal structures of artocarpin, a Moraceae lectin with mannose specificity, and its complex with methyl-alpha-D-mannose: implications to the generation of carbohydrate specificity.
J.Mol.Biol., 317:237-247, 2002

PubMed Abstract: The seeds of jack fruit (Artocarpus integrifolia) contain two tetrameric lectins, jacalin and artocarpin. Jacalin was the first lectin found to exhibit the beta-prism I fold, which is characteristic of the Moraceae plant lectin family. Jacalin contains two polypeptide chains produced by a post-translational proteolysis which has been shown to be crucial for generating its specificity for galactose. Artocarpin is a single chain protein with considerable sequence similarity with jacalin. It, however, exhibits many properties different from those of jacalin. In particular, it is specific to mannose. The structures of two crystal forms, form I and form II, of the native lectin have been determined at 2.4 and 2.5 A resolution, respectively. The structure of the lectin complexed with methyl-alpha-mannose, has also been determined at 2.9 A resolution. The structure is similar to jacalin, although differences exist in details. The crystal structures and detailed modelling studies indicate that the following differences between the carbohydrate binding sites of artocarpin and jacalin are responsible for the difference in the specificities of the two lectins. Firstly, artocarpin does not contain, unlike jacalin, an N terminus generated by post-translational proteolysis. Secondly, there is no aromatic residue in the binding site of artocarpin whereas there are four in that of jacalin. A comparison with similar lectins of known structures or sequences, suggests that, in general, stacking interactions with aromatic residues are important for the binding of galactose while such interactions are usually absent in the carbohydrate binding sites of mannose-specific lectins with the beta-prism I fold.

PubMed: 11902840
DOI: 10.1006/jmbi.2001.5432

Experimental method

X-RAY DIFFRACTION (2.4 Å)