Article date: 1991/3/1
PubMed ID: 3037384
Journal name: Neurochemical research (ISSN: 0364-3190)
The GABAA-benzodiazepine receptor protein from bovine brain was purified by affinity chromatography and the subunit composition examined by gel electrophoresis in sodium dodecyl sulfate. Protein staining revealed a doublet at 51-53 kDa, a band at 55 kDa, and a broad band at 57-59 kDa. The 51 and 53 kDa bands co-migrated with the alpha 1 and alpha 2 gene products identified by Western blotting with subtype-specific antibodies. These two bands were also photoaffinity labeled by [3H]flunitrazepam, as was a breakdown product at 44 kDa. Partial sequencing of proteolytic fragments of these polypeptides yielded sequences found in all alpha clones, and identified the benzodiazepine binding site within residues 8-297 and probably between 106-297 of alpha 1; the 44 kDa and 31 kDa bands yielded fragments containing alpha 3 sequence. The native alpha 3 polypeptide was identified with subtype-specific antibody at 57 kDa overlapping with the two major bands photolabeled with [3H]muscimol at 55 and 58 kDa. Antisera to a beta-selective peptide recognized four bands at 60, 58, 57 and 55 kDa. Thus, one can identify 6-8 distinct polypeptides with the possibility of another 4-6 in purified GABAA receptor proteins, depending on brain region, consistent with the family of gene products suggested by molecular cloning.
Author List: Olsen R W, Bureau M H, Endo S, Smith G
Publication Types: Comparative Study; Journal Article; Research Support, U.S. Gov't, P.H.S.
Substances mentioned in the article: Affinity Labels; Peptide Fragments; Receptors, GABA-A; Muscimol; Flunitrazepam; Serine Endopeptidases; glutamyl endopeptidase;
Mesh terms: Affinity Labels; Amino Acid Sequence; Animals; Blotting, Western; Brain Chemistry; Cattle; Electrophoresis, Polyacrylamide Gel; Flunitrazepam/metabolism; Humans; Molecular Sequence Data; Molecular Weight; Muscimol/metabolism; Peptide Fragments/chemistry; Photochemistry; Rats; Receptors, GABA-A/chemistry; Serine Endopeptidases/metabolism;
Citations: - 2155149