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Structure of L-amino acid oxidase from Calloselasma rhodostoma in complex with L-phenylalanineStructure of L-amino acid oxidase from Calloselasma rhodostoma in complex with L-phenylalanine
Structural highlights
FunctionOXLA_CALRH Catalyzes an oxidative deamination of predominantly hydrophobic and aromatic L-amino acids, thus producing hydrogen peroxide that may contribute to the diverse toxic effects of this enzyme. Exhibits diverse biological activities, such as hemorrhage, hemolysis, edema, apoptosis of vascular endothelial cells or tumor cell lines, antibacterial and antiparasitic activities, as well as regulation of platelet aggregation. Its effect on platelets is controversial, since it either induces aggregation or inhibits agonist-induced aggregation. These different effects are probably due to different experimental conditions (By similarity). 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 PubMedL-Amino acid oxidase is a dimeric glycosylated flavoenzyme, a major constituent of the venom-from the snake Calloselasma rhodostoma. The enzyme exhibits apoptosis inducing effects as well as antibacterial and anti-HIV activities. The structure of l-amino acid oxidase with its substrate (L-phenylalanine) has been refined to a resolution of 1.8 A. The complex structure reveals the substrate bound to the reduced flavin (FADred). Alternative conformations for the key residues His223 and Arg322 are evident, suggesting a dynamic active site. Furthermore, conformational changes are apparent for the isoalloxazine ring; the three-ring system exhibits more bending around the N5-N10 axis compared to the oxidized flavin. The implications of the observed dynamics on the mechanism of catalysis are discussed. Inspection of buried surfaces in the enzyme reveals a Y-shaped channel system extending from the external surface of the protein to the active site. One portion of this channel may serve as the entry path for O2 during the oxidative half-reaction. The second region, separated from the proposed O2 channel by the N terminus (residues 8-16) of the protein, may play a role in H2O2 release. Interestingly, the latter portion of the channel would direct the H2O2 product to the exterior surface of the protein, near the glycan moiety, thought to anchor the enzyme to the host cell. This channel location may explain the ability of the enzyme to localize H2O2 to the targeted cell and thus induce the apoptotic effect. Crystal structure of LAAO from Calloselasma rhodostoma with an L-phenylalanine substrate: insights into structure and mechanism.,Moustafa IM, Foster S, Lyubimov AY, Vrielink A J Mol Biol. 2006 Dec 15;364(5):991-1002. Epub 2006 Sep 16. PMID:17046020[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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