| the c-terminal and beta-wing regions of ammodytoxin a, a neurotoxic phospholipase a2 from vipera ammodytes ammodytes, are critical for binding to factor xa and for anticoagulant effect. | ammodytoxin a (atxa) from the venom of vipera ammodytes ammodytes belongs to group iia secreted phospholipase a2 (spla2), for which the major pathologic activity is presynaptic neurotoxicity. we show here that this toxin also affects hemostasis because it exhibits strong anticoagulant activity. atxa binds directly to human coagulation factor xa (fxa) with kdapp of 32 nm, thus inhibiting the activity of the prothrombinase complex with an ic50 of 20 nm. to map the fxa-interaction site on atxa, var ... | 2006 | 16039772 |
| mrna secondary structure can greatly affect production of recombinant phospholipase a(2) toxins in bacteria. | the neurotoxic activity of ammodytoxin a (atxa), a phospholipase a(2) from vipera ammodytes ammodytes venom, has been investigated by protein engineering. with the aim of obtaining atxa as a non-fused protein in the bacterial cytoplasm and avoiding problems with incomplete cleavage in vivo of the initial met preceding the first residue (ser1), a double mutant (s1a/e4q) was prepared and expressed in escherichia coli. immunoblotting of the bacterial lysate showed that the mutant was synthesized at ... | 2002 | 11821126 |
| expression of fully active ammodytoxin a, a potent presynaptically neurotoxic phospholipase a2, in escherichia coli. | a cdna encoding the most presynaptically neurotoxic phospholipase a2, ammodytoxin a, from the venom of the long-nosed viper (vipera ammodytes ammodytes) has been expressed in escherichia coli. ammodytoxin a was produced as a fusion protein with the 81 n-terminal residues of adenylate kinase followed by the tetrapeptide recognition site for factor xa (iegr) just preceding the first amino acid residue of the toxin. the fusion protein was expressed under the control of tac promoter without iptg ind ... | 1993 | 8224227 |