title: Crystal structure of tetranectin, a trimeric plasminogen-binding protein with an alpha-helical coiled coil.
abstract: Tetranectin is a plasminogen kringle 4-binding protein. The crystal structure has been determined at 2.8 A resolution using molecular replacement. Human tetranectin is a homotrimer forming a triple alpha-helical coiled coil. Each monomer consists of a carbohydrate recognition domain (CRD) connected to a long alpha-helix. Tetranectin has been classified in a distinct group of the C-type lectin superfamily but has structural similarity to the proteins in the group of collectins. Tetranectin has three intramolecular disulfide bridges. Two of these are conserved in the C-type lectin superfamily, whereas the third is present only in long-form CRDs. Tetranectin represents the first structure of a long-form CRD with intact calcium-binding sites. In tetranectin, the third disulfide bridge tethers the CRD to the long helix in the coiled coil. The trimerization of tetranectin as well as the fixation of the CRDs relative to the helices in the coiled coil indicate a demand for high specificity in the recognition and binding of ligands.
authors.affiliation: Department of Medicinal Chemistry, Royal Danish School of Pharmacy, Copenhagen. bettina@medchem.dfh.dk
authors.forename: B B
authors.initials: BB
authors.lastname: Nielsen
authors.forename: J S
authors.initials: JS
authors.lastname: Kastrup
authors.forename: H
authors.initials: H
authors.lastname: Rasmussen
authors.forename: T L
authors.initials: TL
authors.lastname: Holtet
authors.forename: J H
authors.initials: JH
authors.lastname: Graversen
authors.forename: M
authors.initials: M
authors.lastname: Etzerodt
authors.forename: H C
authors.initials: HC
authors.lastname: Thøgersen
authors.forename: I K
authors.initials: IK
authors.lastname: Larsen
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001798:Blood Proteins / Q000737:chemistry* / Q000378:metabolism; D050260:Carbohydrate Metabolism; D018360:Crystallography, X-Ray; D006801:Humans; D037181:Lectins, C-Type; D008969:Molecular Sequence Data; D010958:Plasminogen; D011485:Protein Binding; D011487:Protein Conformation; D051381:Rats; D011994:Recombinant Proteins / Q000737:chemistry; D017386:Sequence Homology, Amino Acid
chemical_list: D001798:Blood Proteins; D037181:Lectins, C-Type; D011994:Recombinant Proteins; C048648:tetranectin; D010958:Plasminogen