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New crystal structure of human tear lipocalin in complex with 1,4-butanediol in space group P21
Structural highlights
FunctionLCN1_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 PubMedTear lipocalin (TLC) with the bound artificial ligand 1,4-butanediol has been crystallized in space group P2(1) with four protein molecules in the asymmetric unit and its X-ray structure has been solved at 2.6 A resolution. TLC is a member of the lipocalin family that binds ligands with diverse chemical structures, such as fatty acids, phospholipids and cholesterol as well as microbial siderophores and the antibiotic rifampin. Previous X-ray structural analysis of apo TLC crystallized in space group C2 revealed a rather large bifurcated ligand pocket and a partially disordered loop region at the entrace to the cavity. Analysis of the P2(1) crystal form uncovered major conformational changes (i) in beta-strands B, C and D, (ii) in loops 1, 2 and 4 at the open end of the beta-barrel and (iii) in the extended C-terminal segment, which is attached to the beta-barrel via a disulfide bridge. The structural comparison indicates high conformational plasticity of the loop region as well as of deeper parts of the ligand pocket, thus allowing adaptation to ligands that differ vastly in size and shape. This illustrates a mechanism for promiscuity in ligand recognition which may also be relevant for some other physiologically important members of the lipocalin protein family. A new crystal form of human tear lipocalin reveals high flexibility in the loop region and induced fit in the ligand cavity.,Breustedt DA, Chatwell L, Skerra A Acta Crystallogr D Biol Crystallogr. 2009 Oct;65(Pt 10):1118-25. Epub 2009, Sep 16. PMID:19770509[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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