4wmq
Structure of Human Intelectin-1
Structural highlights
FunctionITLN1_HUMAN Has no effect on basal glucose uptake but enhances insulin-stimulated glucose uptake in adipocytes. Increases AKT phosphorylation in the absence and presence of insulin. May play a role in the defense system against microorganisms. May specifically recognize carbohydrate chains of pathogens and bacterial components containing galactofuranosyl residues, in a calcium-dependent manner. May be involved in iron metabolism.[1] [2] Publication Abstract from PubMedThe glycans displayed on mammalian cells can differ markedly from those on microbes. Such differences could, in principle, be 'read' by carbohydrate-binding proteins, or lectins. We used glycan microarrays to show that human intelectin-1 (hIntL-1) does not bind known human glycan epitopes but does interact with multiple glycan epitopes found exclusively on microbes: beta-linked D-galactofuranose (beta-Galf), D-phosphoglycerol-modified glycans, heptoses, D-glycero-D-talo-oct-2-ulosonic acid (KO) and 3-deoxy-D-manno-oct-2-ulosonic acid (KDO). The 1.6-A-resolution crystal structure of hIntL-1 complexed with beta-Galf revealed that hIntL-1 uses a bound calcium ion to coordinate terminal exocyclic 1,2-diols. N-acetylneuraminic acid (Neu5Ac), a sialic acid widespread in human glycans, has an exocyclic 1,2-diol but does not bind hIntL-1, probably owing to unfavorable steric and electronic effects. hIntL-1 marks only Streptococcus pneumoniae serotypes that display surface glycans with terminal 1,2-diol groups. This ligand selectivity suggests that hIntL-1 functions in microbial surveillance. Recognition of microbial glycans by human intelectin-1.,Wesener DA, Wangkanont K, McBride R, Song X, Kraft MB, Hodges HL, Zarling LC, Splain RA, Smith DF, Cummings RD, Paulson JC, Forest KT, Kiessling LL Nat Struct Mol Biol. 2015 Jul 6. doi: 10.1038/nsmb.3053. PMID:26148048[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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