Characterization of the omega-conotoxin target. Evidence for tissue-specific heterogeneity in calcium channel types

Journal Article · Tue Feb 10 04:00:00 EST 1987 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00377a024· OSTI ID:6524553

Cruz, L J; Johnson, D S; Olivera, B M

Omega-Conotoxin GVIA (omega-CgTx-VIA) is a 27 amino acid peptide from the venom of the fish-hunting snail, Conus geographus, that blocks voltage-activated Ca channels. The characterization of a biologically active, homogeneous /sup 125/I-labeled monoiodinated Tyr/sup 22/ derivative of omega-conotoxin GVIA and its use in binding and cross-linking studies are described. The /sup 125/I-labeled toxin is specifically cross-linked to a receptor protein with an apparent M/sub r/ of 135,000. The stoichiometry between omega-conotoxin and nitrendipine binding sites in different chick tissues was determined. Skeletal muscle has a high concentration of (/sup 3/H)nitrendipine binding sites but no detectable omega-conotoxin sites. Brain microsomes have both binding sites, but omega-conotoxin targets are in excess. These results, combined with recent electrophysiological studies define four types of Ca channels in chick tissues, N, T, L/sub n/ (omega sensitive), and L/sub m/ (omega insensitive), and are consistent with the hypothesis that the ..cap alpha..-subunits of certain neuronal Ca/sup 2 +/ channels (L/sub n/, N) are the molecular targets of omega-conotoxin GVIA.

• Research Organization: Univ. of Utah, Salt Lake City
• OSTI ID: 6524553
• Journal Information: Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 26:3; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550601* -- Medicine-- Unsealed Radionuclides in Diagnostics
62 RADIOLOGY AND NUCLEAR MEDICINE
ALKALI METAL COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
AMINO ACIDS
ANIMALS
ANTIGENS
BETA DECAY RADIOISOTOPES
BIRDS
BODY
BRAIN
CALCIUM COMPOUNDS
CARBOXYLIC ACIDS
CELL CONSTITUENTS
CENTRAL NERVOUS SYSTEM
CHEMICAL REACTIONS
CHICKENS
CHROMATOGRAPHY
CROSS-LINKING
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
ELECTROPHORESIS
FOWL
HALIDES
HALOGEN COMPOUNDS
HALOGENATION
HYDROXY ACIDS
INORGANIC PHOSPHORS
INTERMEDIATE MASS NUCLEI
IODIDES
IODINATION
IODINE 125
IODINE COMPOUNDS
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LABELLED COMPOUNDS
LIQUID COLUMN CHROMATOGRAPHY
MATERIALS
MEMBRANE PROTEINS
MICROSOMES
MOLECULAR WEIGHT
MUSCLES
NERVOUS SYSTEM
NUCLEI
ODD-EVEN NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANOIDS
ORGANS
PHOSPHORS
POLYMERIZATION
PROTEINS
RADIOISOTOPES
RADIORECEPTOR ASSAY
RECEPTORS
SEPARATION PROCESSES
SODIUM COMPOUNDS
SODIUM IODIDES
TOXIC MATERIALS
TOXINS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
TYROSINE
VERTEBRATES