1x89
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Crystal structure of Siderocalin (NGAL, Lipocalin 2) complexed with Carboxymycobactin S
OverviewOverview
Siderocalin, a member of the lipocalin family of binding proteins, is, found in neutrophil granules, uterine secretions, and at markedly elevated, levels in serum and synovium during bacterial infection; it is also, secreted from epithelial cells in response to inflammation or, tumorigenesis. Identification of high-affinity ligands, bacterial, catecholate-type siderophores (such as enterochelin), suggested a possible, function for siderocalin: an antibacterial agent, complementing the, general antimicrobial innate immune system iron-depletion strategy, sequestering iron as ferric siderophore complexes. Supporting this, hypothesis, siderocalin is a potent bacteriostatic agent in vitro under, iron-limiting conditions and, when knocked out, renders mice remarkably, susceptible to bacterial infection. Here we show that siderocalin also, binds soluble siderophores of mycobacteria, including M. tuberculosis:, carboxymycobactins. Siderocalin employs a degenerate recognition mechanism, to cross react with these dissimilar types of siderophores, broadening the, potential utility of this innate immune defense.
About this StructureAbout this Structure
1X89 is a Single protein structure of sequence from Homo sapiens with CM1 as ligand. Full crystallographic information is available from OCA.
ReferenceReference
Siderocalin (Lcn 2) also binds carboxymycobactins, potentially defending against mycobacterial infections through iron sequestration., Holmes MA, Paulsene W, Jide X, Ratledge C, Strong RK, Structure. 2005 Jan;13(1):29-41. PMID:15642259
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