3a0d
From Proteopedia
Crystal Structure of Polygonatum cyrtonema lectin (PCL) complexed with monomannoside
Structural highlights
Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedPolygonatum cyrtonema lectin (PCL) is a novel anti-HIV mannose-binding lectin from Galanthus nivalis agglutinin (GNA)-related lectin family. Crystal structures of ligand-free PCL and its complexes with monomannoside and alpha1-3 dimannoside have been determined. The ligand-free PCL is dimeric, with both subunits adopt the beta-prism II fold. PCL subunit binds mannose using a potential bivalent mode instead of the usual trivalent mode, in which carbohydrate-binding site (CBS) I and CBS III adopt the conserved mannose-binding motif of QXDXNXVXY (X is one of any amino acid residues) as observed in other structurally characterized GNA-related lectins, while CBS II adopts a modified motif with residues Gln58 and Asp60, which are critical for mannose-binding, substituted by His58 and Asn60, respectively. As a result, CBS II is unfit for mannose-binding. In the mannoside complexes, ligand-bindings only occur at CBS I which provides the specificity for alpha1-3 dimannoside. CBS II and CBS III are cooperatively occupied by a well-ordered sulfate ion, through which the individual dimers are cross-linked to form a unique super-structure of 3(2) helical lattice. Surveying the sequences of GNA-related lectins revealed that the modified binding motif of CBS II is widely distributed in the Liliaceae family as an intrinsic structural element. There is evidence that other GNA-related lectins will also adopt the similar super-structure as PCL. Thus PCL structure, unique in ligand-binding mode, may represent a novel type of structure of GNA-related lectins. Comparative analyses indicated that the dimer-based super-structure may play a primary role in the anti-HIV property of PCL. Crystal structures of a novel anti-HIV mannose-binding lectin from Polygonatum cyrtonema Hua with unique ligand-binding property and super-structure.,Ding J, Bao J, Zhu D, Zhang Y, Wang DC J Struct Biol. 2010 Sep;171(3):309-17. Epub 2010 May 28. PMID:20546901[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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