3u3u
Crystal structure of the tablysin-15-leukotriene E4 complex
Structural highlights
FunctionLYSF_TABYA Anti-inflammatory scavenger of eicosanoids and antithrombotic protein that inhibits platelets aggregation induced by collagen, ADP and convulxin (GPVI agonist) (PubMed:21475772, PubMed:22311975). Exhibits high affinity binding for glycoprotein IIb-IIIa receptor (ITGA2B/ITGB3) and endothelial cell alphaVbeta3 (ITGAV/ITGB3) integrins, but not for alpha-5/beta-1 or alpha-2/beta-1 (PubMed:21475772). Accordingly, it blocks endothelial cell adhesion to vitronectin (IC(50)~1 nM) and marginally to fibronectin (IC(50)~1 uM), but not to collagen (PubMed:21475772). It also inhibits fibroblast growth factor (FGF)-induced endothelial cell proliferation, and attenuates tube formation in vitro (PubMed:21475772). In addition, it dose-dependently attenuates thrombus formation to collagen under flow (PubMed:21475772). Also binds proinflammatory cysteinyl leukotrienes (leukotrienes C4 (LTC4), D4 (LTD4) and E4 (LTE4)) with submicromolar affinities (PubMed:22311975).[1] [2] Publication Abstract from PubMedThe antihemostatic/antiangiogenic protein tablysin-15 is a member of the cysteine-rich secretory, antigen 5 and pathogenesis-related 1 protein (CAP) superfamily and has been shown to bind the integrins alphaIIbbeta3 and alphaVbeta3 by means of an Arg-Gly-Asp (RGD) tripeptide sequence. Here we describe the X-ray crystal structure of tablysin-15 and show that the RGD motif is located in a novel structural context. The motif itself is contained in a type II beta-turn structure that is similar in its conformation to the RGD sequence of the cyclic pentapeptide cilengitide when bound to integrin alphaVbeta3. The CAP domain also contains a hydrophobic channel that appears to bind a fatty acid molecule in the crystal structure after purification from Escherichia coli. After delipidation of the protein, tablysin-15 was found to bind proinflammatory cysteinyl leukotrienes with submicromolar affinities. The structure of the leukotriene E4 (LTE4)-tablysin-15 complex shows that the ligand binds with the non-functionalized end of the fatty acid chain buried in the hydrophobic pocket, while the carboxylate end of the ligand binds forms hydrogen bond/salt bridge interactions with polar side chains at the channel entrance. Therefore, tablysin-15 functions as an inhibitor of integrin function and as an anti-inflammatory scavenger of eicosanoids. Structure of a protein having inhibitory disintegrin and leukotriene scavenging functions contained in a single domain.,Xu X, Francischetti IM, Lai R, Ribeiro JM, Andersen JF J Biol Chem. 2012 Feb 6. PMID:22311975[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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