1xki | pdb_00001xki

Crystal structure of human tear lipocalin/von Ebners gland protein

spinqualitylabelsall models 1xki, resolution 1.80Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1xki is a 1 chain structure with sequence from Human. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: CL, ZN Gene: LCN1 (HUMAN) Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [LCN1_HUMAN] Could play a role in taste reception. Could be necessary for the concentration and delivery of sapid molecules in the gustatory system. Can bind various ligands, with chemical structures ranging from lipids and retinoids to the macrocyclic antibiotic rifampicin and even to microbial siderophores. Exhibits an extremely wide ligand pocket. 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 PubMed In contrast with earlier assumptions, which classified human tear lipocalin (Tlc) as an outlier member of the lipocalin protein family, the 1.8-A resolution crystal structure of the recombinant apoprotein confirms the typical eight-stranded antiparallel beta-barrel architecture with an alpha-helix attached to it. The fold of Tlc most closely resembles the bovine dander allergen Bos d 2, a well characterized prototypic lipocalin, but also reveals similarity with beta-lactoglobulin. However, compared with other lipocalin structures Tlc exhibits an extremely wide ligand pocket, whose entrance is formed by four partially disordered loops. The cavity deeply extends into the beta-barrel structure, where it ends in two distinct lobes. This unusual structural feature explains the known promiscuity of Tlc for various ligands, with chemical structures ranging from lipids and retinoids to the macrocyclic antibiotic rifampin and even to microbial siderophores. Notably, earlier findings of biological activity as a thiol protease inhibitor have no correspondence in the three-dimensional structure of Tlc, rather it appears that its proteolytic fragments could be responsible for this phenomenon. Hence, the present structural analysis sheds new light on the ligand binding activity of this functionally obscure but abundant human lipocalin. The 1.8-A crystal structure of human tear lipocalin reveals an extended branched cavity with capacity for multiple ligands.,Breustedt DA, Korndorfer IP, Redl B, Skerra A J Biol Chem. 2005 Jan 7;280(1):484-93. Epub 2004 Oct 15. PMID:15489503 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Neutrophil gelatinase-associated lipocalin

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