1xx1

Structural basis for ion-coordination and the catalytic mechanism of sphingomyelinases D

spinqualitylabelsall models 1xx1, resolution 1.75Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1xx1 is a 4 chain structure with sequence from Loxosceles laeta. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.75Å Ligands: EPE, MG, SO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function A311_LOXLA Catalyzes the hydrolysis of sphingomyelin. May also acts on other phosphatidyl esters. Induces complement-dependent hemolysis and dermonecrosis. 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 Sphingomyelinases D (SMases D) from Loxosceles spider venom are the principal toxins responsible for the manifestation of dermonecrosis, intravascular hemolysis, and acute renal failure, which can result in death. These enzymes catalyze the hydrolysis of sphingomyelin, resulting in the formation of ceramide 1-phosphate and choline or the hydrolysis of lysophosphatidyl choline, generating the lipid mediator lysophosphatidic acid. This report represents the first crystal structure of a member of the sphingomyelinase D family from Loxosceles laeta (SMase I), which has been determined at 1.75-angstrom resolution using the "quick cryo-soaking" technique and phases obtained from a single iodine derivative and data collected from a conventional rotating anode x-ray source. SMase I folds as an (alpha/beta)8 barrel, the interfacial and catalytic sites encompass hydrophobic loops and a negatively charged surface. Substrate binding and/or the transition state are stabilized by a Mg2+ ion, which is coordinated by Glu32, Asp34, Asp91, and solvent molecules. In the proposed acid base catalytic mechanism, His12 and His47 play key roles and are supported by a network of hydrogen bonds between Asp34, Asp52, Trp230, Asp233, and Asn252. Structural basis for metal ion coordination and the catalytic mechanism of sphingomyelinases D.,Murakami MT, Fernandes-Pedrosa MF, Tambourgi DV, Arni RK J Biol Chem. 2005 Apr 8;280(14):13658-64. Epub 2005 Jan 14. PMID:15654080 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Sphingomyelinase

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