1tn3
THE C-TYPE LECTIN CARBOHYDRATE RECOGNITION DOMAIN OF HUMAN TETRANECTIN
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OverviewOverview
Tetranectin (TN) is a C-type lectin involved in fibrinolysis, being the, only endogenous ligand known to bind specifically to the kringle 4 domain, of plasminogen. TN was originally isolated from plasma, but shows a wide, tissue distribution. Furthermore, TN has been found in the extracellular, matrix of certain human carcinomas, whereas none or little is present in, the corresponding normal tissue. The crystal structure of full-length, trimeric TN (2.8 A resolution) has recently been published [Nielsen et al., (1997). FEBS Lett. 412, 388-396]. The crystal structure of the, carbohydrate recognition domain (CRD) of human TN (TN3) has been, determined separately at 2.0 A resolution in order to obtain detailed, information on the two calcium binding sites. This information is, essential for the elucidation of the specificity of TN towards, oligosaccharides. TN3 crystallizes as a dimer, whereas it appears as a, monomer in solution. The overall fold of TN3 is similar to other known, CRDs. Each monomer is built of two distinct regions, one region consisting, of six beta-strands and two alpha-helices, and the other region is, composed of four loops harboring two calcium ions. The calcium ion at site, 1 forms an eightfold coordinated complex and has Asp116, Glu120, Gly147, Glu150, Asn151, and one water molecule as ligands. The calcium ion at site, 2, which is believed to be involved in recognition and binding of, oligosaccharides, is sevenfold coordinated with ligands Gln143, Asp145, Glu150, Asp165, and two water molecules. One sulfate ion has been located, at the surface of TN3, forming contacts to Glu120, Lys148, Asn106 of a, symmetry-related molecule, and to an ethanol molecule.
About this StructureAbout this Structure
1TN3 is a Single protein structure of sequence from Homo sapiens with CA, SO4 and EOH as ligands. Structure known Active Sites: CA1 and CA2. Full crystallographic information is available from OCA.
ReferenceReference
Structure of the C-type lectin carbohydrate recognition domain of human tetranectin., Kastrup JS, Nielsen BB, Rasmussen H, Holtet TL, Graversen JH, Etzerodt M, Thogersen HC, Larsen IK, Acta Crystallogr D Biol Crystallogr. 1998 Sep 1;54(Pt 5):757-66. PMID:9757090
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