The amino acid region 115-119 of ammodytoxins plays an important role in neurotoxicity.
Quadruple (Y115K/I116K/R118M/N119L) and double (Y115K/I116K) mutants of ammodytoxin A, a presynaptically toxic phospholipase A(2) from Vipera ammodytes ammodytes venom, were prepared and characterized. The enzymatic activity of the quadruple mutant on phosphatidylcholine micelles was threefold higher than that of AtxA, presumably due to higher phospholipid-binding affinity, whereas the activity of the double mutant was twofold lower. The substantial decrease by more than two orders of magnitude in the lethal potency of both mutants, together with their decreased binding affinity for neuronal receptors, indicates involvement of the amino acid region 115-119 in neurotoxicity. The similar decrease of toxicity for the two mutants points to the importance of the residues Y115 and I116.
Ivanovski
G
G
Department of Biochemistry and Molecular Biology, Jozef Stefan Institute, Jamova 39, Ljubljana, SI-1000, Slovenia.
Copic
A
A
Krizaj
I
I
Gubensek
F
F
Pungercar
J
J
D000595:Amino Acid Sequence; D019943:Amino Acid Substitution / Q000235:genetics; D000818:Animals; D001667:Binding, Competitive; D002540:Cerebral Cortex; D054501:Group II Phospholipases A2; D007928:Lethal Dose 50; D051379:Mice; D008823:Micelles; D008958:Models, Molecular; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009154:Mutation / Q000235:genetics; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D010713:Phosphatidylcholines / Q000378:metabolism; D010741:Phospholipases A / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism* / Q000633:toxicity; D011487:Protein Conformation; D011956:Receptors, Cell Surface / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism / Q000633:toxicity; D016415:Sequence Alignment; D013552:Swine; D014757:Viper Venoms / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism / Q000633:toxicity*
D008823:Micelles; D010713:Phosphatidylcholines; D011956:Receptors, Cell Surface; D011993:Recombinant Fusion Proteins; D014757:Viper Venoms; C068117:ammodytoxin A; D010741:Phospholipases A; D054501:Group II Phospholipases A2; C060161:ammodytoxin C