2h4c
Structure of Daboiatoxin (heterodimeric PLA2 venom)
Structural highlights
FunctionPA2AA_DABSI Heterodimer (A and B chains): phospholipase A2 that acts as a presynaptic neurotoxin and shows a PLA2 activity of 1377 umol/min/mg. In vivo, induces edema and produces neurotoxic symptoms in mice. Also exhibits indirect hemolysis, a strong myonecrotic activity and cytotoxicity. PLA2 catalyzes the calcium-dependent hydrolysis of the 2-acyl groups in 3-sn-phosphoglycerides. Monomer: Snake venom phospholipase A2 (PLA2) that shows a PLA2 activity of 578 umol/min/mg. 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 PubMedRussell's viper (Vipera russelli, also known as Daboia russelli) is one of the major causes of fatal snakebites. To date, five Daboia russelli subspecies have been recognized. Daboiatoxin (DbTx) is the main lethal phospholipase A(2) (PLA(2)) toxin in the venom of D. russelli siamensis (Myanmar viper) and has strong neurotoxic, myotoxic and cytotoxic activities. DbTx and its homologous neurotoxins viperotoxin F from D. russelli formosensis (Taiwan viper) and vipoxin from the Bulgarian sand viper V. ammodytes meridionalis consist of complexes between a nontoxic acidic PLA(2) protein and an enzymatically active basic PLA(2). DbTx and viperotoxin F are presynaptic toxins, while vipoxin is postsynaptic. The two chains of DbTx have been separated and their PLA(2) enzymatic activity has been measured using the secretory PLA(2) assay kit. The enzymatic activity of DbTx chain B is reduced by 30% of its original activity by chain A in a unimolar ratio, thus indicating that DbTx chain A acts as an inhibitor. The lethal activity of the two chains has also been studied in male albino mice and chain A is less lethal than chain B. The crystal structure of DbTx has also been determined and its structural details are compared with those of the two homologues. Furthermore, an attempt is made to correlate the sequence and structural determinants of these toxins with their enzymatic activities and their pharmacological effects. Structural and pharmacological comparison of daboiatoxin from Daboia russelli siamensis with viperotoxin F and vipoxin from other vipers.,Gopalan G, Thwin MM, Gopalakrishnakone P, Swaminathan K Acta Crystallogr D Biol Crystallogr. 2007 Jun;63(Pt 6):722-9. Epub 2007, May 15. PMID:17505111[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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