title: Synthesis and characterization of an N-terminal-specific 125I-photoaffinity derivative of mu-Conotoxin GIIIA which binds to the voltage-dependent sodium channel.
abstract: An N-terminal, iodinatable photoaffinity derivative of mu-Conotoxin GIIIA, 4-Azido-salicylyl-mu-Conotoxin GIIIA (CTXASA), was synthesized by solid phase peptide synthesis. The binding of 125I-CTXASA to the voltage dependent sodium channel from electroplax of Electrophorus electricus was specific, as demonstrated by saturation binding experiments. Using autoradiography, 125I-CTXASA labeled a protein with a molecular mass of 260 kDa, consistent with the apparent molecular mass of the sodium channel. This labeling could be suppressed by excess of tetrodotoxin and mu-Conotoxin GIIIA.
authors.affiliation: Max-Planck-Institut für Biophysik, Frankfurt am Main, FRG.
authors.forename: S
authors.initials: S
authors.lastname: Becker
authors.forename: R
authors.initials: R
authors.lastname: Liebe
authors.forename: R D
authors.initials: RD
authors.lastname: Gordon
mesh_terms: D000345:Affinity Labels / Q000138:chemical synthesis / Q000378:metabolism*; D001386:Azides / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism*; D001665:Binding Sites; D002851:Chromatography, High Pressure Liquid; D020916:Conotoxins; D004591:Electrophoresis, Polyacrylamide Gel; D007457:Iodine Radioisotopes; D007553:Isotope Labeling; D008970:Molecular Weight; D010456:Peptides, Cyclic / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D010777:Photochemistry; D015222:Sodium Channels / Q000378:metabolism*; D013779:Tetrodotoxin / Q000494:pharmacology
chemical_list: D000345:Affinity Labels; D001386:Azides; D020916:Conotoxins; D007457:Iodine Radioisotopes; D010456:Peptides, Cyclic; D015222:Sodium Channels; C046101:conotoxin GIII; C066351:mu conotoxin GIIIA, 4-azidosalicylyl-; D013779:Tetrodotoxin