Lys-64 of the A chain is involved in the enzymatic activity and neurotoxic effect of beta-bungarotoxin.
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.
Chang
Long-Sen
LS
Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung 804, Taiwan, ROC. lschang@mail.nsysu.edu.tw
Chu
Yuan-Ping
YP
Cheng
Yun-Ching
YC
Liou
Jau-Cheng
JC
Yang
Chen-Chung
CC
D000595:Amino Acid Sequence; D000818:Animals; D002038:Bungarotoxins / Q000737:chemistry* / Q000302:isolation & purification / Q000633:toxicity*; D002645:Chickens; D004594:Electrophysiology; D066298:In Vitro Techniques; D008239:Lysine / Q000737:chemistry*; D008969:Molecular Sequence Data; D009119:Muscle Contraction / Q000187:drug effects; D009469:Neuromuscular Junction / Q000187:drug effects; D009498:Neurotoxins / Q000737:chemistry*; D011487:Protein Conformation; D011732:Pyridoxal Phosphate; D012910:Snake Venoms; D014981:Xenopus
D002038:Bungarotoxins; D009498:Neurotoxins; D012910:Snake Venoms; D011732:Pyridoxal Phosphate; D008239:Lysine