4ihz
Crystal structure of CrataBL, a trypsin inhibitor from Crataeva tapia
Structural highlights
FunctionLECB1_CRATA Glucose and N-acetylglucosamine binding lectin. Has hemagglutinating activity against human and rabbit erythrocytes which does not require divalent cations. Inhibits factor Xa and, to a lesser extent, trypsin. Does not inhibit neutrophil elastase, human plasma kallikrein, papain, human plasmin, porcine pancreatic kallikrein and bovin chymotrypsin. Has insecticidal activity against the termite species N.corniger. Induces apoptosis in prostrate cancer cell lines DU145 and PC3.[1] [2] Publication Abstract from PubMedA protein isolated from the bark of Crataeva tapia (CrataBL) is both a Kunitz-type plant protease inhibitor and a lectin. We have determined the amino acid sequence and three-dimensional structure of CrataBL, as well as characterized its selected biochemical and biological properties. We found two different isoforms of CrataBL isolated from the original source, differing in positions 31 (Pro/Leu); 92 (Ser/Leu); 93 (Ile/Thr); 95 (Arg/Gly) and 97 (Leu/Ser). CrataBL showed relatively weak inhibitory activity against trypsin (Kiapp = 43 microM) and was more potent against Factor Xa (Kiapp = 8.6 microM), but was not active against a number of other proteases. We have confirmed that CrataBL contains two glycosylation sites and forms a dimer at high concentration. The high-resolution crystal structures of two different crystal forms of isoform II verified the beta-trefoil fold of CrataBL and have shown the presence of dimers consisting of two almost identical molecules making extensive contacts ( approximately 645 A2). The structure differs from those of the most closely related proteins by the lack of the N-terminal beta-hairpin. In experiments aimed at investigating the biological properties of CrataBL, we have shown that addition of 40 microM of the protein for 48 h caused maximum growth inhibition in MTT assay (47% of DU145 cells and 43% of PC3 cells). The apoptosis of DU145 and PC3 cell lines was confirmed by flow cytometry using Annexin V/FITC and propidium iodide staining. Treatment with CrataBL resulted in the release of mitochondrial cytochrome c and in the activation of caspase-3 in DU145 and PC3 cells. Crystal Structure of Bark Protein (CrataBL) and Its Effect in Human Prostate Cancer Cell Lines.,Ferreira RD, Zhou D, Ferreira JG, Silva MC, Silva-Lucca RA, Mentele R, Paredes-Gamero EJ, Bertolin TC, Dos Santos Correia MT, Paiva PM, Gustchina A, Wlodawer A, Oliva ML PLoS One. 2013 Jun 18;8(6):e64426. Print 2013. PMID:23823708[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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