title: Structural and functional features of noxiustoxin: a K+ channel blocker.
abstract: Binding of [125I]-Noxiustoxin to rat brain synaptosome membranes and displacement with synthetic peptides corresponding to the amino acid sequence of Noxiustoxin, show that the N-terminal segment of this toxin is implicated in the recognition of brain K(+)-channels. Cleavage of NTX with cyanogen bromide, endopeptidase V8 from Staphylococcus aureus and endopeptidase Lys-C support these findings. On the contrary, a synthetic C-terminal tetradecapeptide of charybodotoxin (ChTX), shows that in this K(+)-channel blocker, the C-terminal region, rather than the N-terminal is capable of displacing 125[I]-NTX binding to brain membranes.
authors.affiliation: Department of Molecular Recognition and Structural Biology, Universidad Nacional Autónoma de México, Avenida Universidad, Cuernavaca, Mexico.
authors.forename: G B
authors.initials: GB
authors.lastname: Gurrola
authors.forename: L D
authors.initials: LD
authors.lastname: Possani
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D018999:Charybdotoxin / Q000737:chemistry*; D007091:Image Processing, Computer-Assisted; D008958:Models, Molecular; D008969:Molecular Sequence Data; D026902:Potassium Channel Blockers; D011485:Protein Binding; D011869:Radioligand Assay; D051381:Rats; D012604:Scorpion Venoms / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D013329:Structure-Activity Relationship; D013574:Synaptosomes / Q000187:drug effects* / Q000378:metabolism
chemical_list: D026902:Potassium Channel Blockers; D012604:Scorpion Venoms; D018999:Charybdotoxin; C052567:noxiustoxin