1vbp
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(New page: 200px<br /><applet load="1vbp" size="450" color="white" frame="true" align="right" spinBox="true" caption="1vbp, resolution 3.50Å" /> '''Crystal structure of...)
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Revision as of 19:55, 24 November 2007
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Crystal structure of artocarpin-mannopentose complex
Overview
Artocarpin, a tetrameric lectin of molecular mass 65 kDa, is one of the, two lectins extracted from the seeds of jackfruit. The structures of the, complexes of artocarpin with mannotriose and mannopentose reported here, together with the structures of artocarpin and its complex with, Me-alpha-mannose reported earlier, show that the lectin possesses a, deep-seated binding site formed by three loops. The binding site can be, considered as composed of two subsites; the primary site and the secondary, site. Interactions at the primary site composed of two of the loops, involve mainly hydrogen bonds, while those at the secondary site, comprising the third loop are primarily van der Waals in nature., Mannotriose in its complex with the lectin interacts through all the three, mannopyranosyl residues; mannopentose interacts with the protein using at, least three of the five mannose residues. The complexes provide a, structural explanation for the carbohydrate specificities of artocarpin. A, detailed comparison with the sugar complexes of heltuba, the only other, mannose-specific jacalin-like lectin with known three-dimensional, structure in sugar-bound form, establishes the role of the sugar-binding, loop constituting the secondary site, in conferring different, specificities at the oligosaccharide level. This loop is four residues, longer in artocarpin than in heltuba, providing an instance where, variation in loop length is used as a strategy for generating carbohydrate, specificity.
About this Structure
1VBP is a Protein complex structure of sequences from Artocarpus integrifolia with SO4 as ligand. Full crystallographic information is available from OCA.
Reference
Structural basis for the carbohydrate specificities of artocarpin: variation in the length of a loop as a strategy for generating ligand specificity., Jeyaprakash AA, Srivastav A, Surolia A, Vijayan M, J Mol Biol. 2004 May 7;338(4):757-70. PMID:15099743
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