Relationship between the binding sites for an alpha-conotoxin and snake venom neurotoxins in the nicotinic acetylcholine receptor from Torpedo californica.
Photoinduced cross-links between the iodinated Lys26-p-azidobenzoyl derivative of neurotoxin II from Naja naja oxiana cobra venom and nicotinic acetylcholine receptor from Torpedo californica (AChR) have been studied in the presence of alpha-conotoxin GI from the marine snail C. geographus. Preincubation of the AChR-enriched membranes with increasing concentrations of alpha-conotoxin GI protects first the gamma subunit from photolabelling and then the delta subunit, the IC50 values being 0.76 and 5.01 microM, respectively. The results obtained, in view of the relevant data in literature, demonstrate that the (alpha + gamma) site, which is the high affinity site for d-tubocurarine, has also a higher affinity for an alpha-conotoxin than the (alpha + delta) containing site. The latter has a somewhat higher affinity than the (alpha + gamma) site towards some naturally occurring snake venom alpha-neurotoxins or their derivatives.
Utkin
Y N
YN
Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences.
Kobayashi
Y
Y
Hucho
F
F
Tsetlin
V I
VI
D000818:Animals; D001665:Binding Sites; D001667:Binding, Competitive; D020916:Conotoxins; D003432:Cross-Linking Reagents; D004546:Elapid Venoms / Q000378:metabolism* / Q000633:toxicity; D017815:Elapidae; D008978:Mollusk Venoms / Q000378:metabolism* / Q000633:toxicity; D009498:Neurotoxins / Q000378:metabolism* / Q000633:toxicity; D010456:Peptides, Cyclic / Q000378:metabolism* / Q000633:toxicity; D011978:Receptors, Nicotinic / Q000187:drug effects* / Q000378:metabolism; D012908:Snails; D014101:Torpedo / Q000378:metabolism
D020916:Conotoxins; D003432:Cross-Linking Reagents; D004546:Elapid Venoms; D008978:Mollusk Venoms; D009498:Neurotoxins; D010456:Peptides, Cyclic; D011978:Receptors, Nicotinic; C029960:conotoxin GI