Lys-64 of the A chain is involved in the enzymatic activity and neurotoxic effect of beta-bungarotoxin

Toxicon. 2005 Feb;45(2):179-85. doi: 10.1016/j.toxicon.2004.10.006.

Abstract

Two beta-bungarotoxin isotoxins BM12 and BM13 were isolated from Bungarus multicinctus (Taiwan banded krait) venom by sequential chromatography on ion-exchange and reverse phase columns. The two toxins have the same A chain, but different B chains. Different phospholipase A2 activity and different potencies in inhibiting the spontaneous enhancement of spontaneous synaptic current frequency and muscle contraction were observed for BM12 and BM13. Nevertheless, modification of Lys-64 in the A chain of BM12 and BM13 similarly reduced in their phospholipase A2 activity and toxicity. The modified derivatives retained their affinity with Ca2+ and their conformation as deduced by CD. These results suggest that Lys-64 of the A chain is involved in the phospholipase A2 activity and in the neurotoxic effect of beta-bungarotoxin.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Bungarotoxins / chemistry*
  • Bungarotoxins / isolation & purification
  • Bungarotoxins / toxicity*
  • Chickens
  • Electrophysiology
  • In Vitro Techniques
  • Lysine / chemistry*
  • Molecular Sequence Data
  • Muscle Contraction / drug effects
  • Neuromuscular Junction / drug effects
  • Neurotoxins / chemistry*
  • Protein Conformation
  • Pyridoxal Phosphate
  • Snake Venoms
  • Xenopus

Substances

  • Bungarotoxins
  • Neurotoxins
  • Snake Venoms
  • Pyridoxal Phosphate
  • Lysine