Chemical modification of the glycine receptor with fluorescein isothiocyanate specifically affects the interaction of glycine with its binding site.
Fluorescein 5'-isothiocyanate (FITC) was used to modify lysine residues of the strychnine-sensitive glycine receptor. Pretreatment of rat spinal cord synaptic plasma membranes with FITC specifically affected the ability of glycine to displace [3H]strychnine binding. Glycine completely prevented the effect of FITC modification, suggesting the existence of lysine group(s) either at or in the vicinity of the agonist binding site. Labeling of purified glycine receptor with FITC indicates that such lysine residue(s) are located in the 48,000 daltons polypeptide. Chemical cleavage of the FITC-labeled 48-kilodalton subunit with N-chlorosuccinimide reveals two major labeled fragments of Mr 13.9 kilodalton and 8.5-kilodalton, respectively, the labeling of each being protected by glycine.
Ruiz Gómez
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A
Departamento de Biología Molecular, Universidad Autónoma de Madrid, Spain.
Fernández-Shaw
C
C
Valdivieso
F
F
Mayor
F
F
D000818:Animals; D055598:Chemical Phenomena; D002621:Chemistry; D016650:Fluorescein-5-isothiocyanate; D005452:Fluoresceins / Q000494:pharmacology*; D005456:Fluorescent Dyes; D005998:Glycine / Q000378:metabolism* / Q000494:pharmacology; D008239:Lysine; D008297:Male; D008526:Medulla Oblongata / Q000378:metabolism; D008970:Molecular Weight; D010446:Peptide Fragments / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D018009:Receptors, Glycine; D017981:Receptors, Neurotransmitter / Q000187:drug effects / Q000378:metabolism*; D013116:Spinal Cord / Q000378:metabolism; D013331:Strychnine / Q000378:metabolism; D013388:Succinimides; D013570:Synaptic Membranes / Q000378:metabolism; D013861:Thiocyanates / Q000494:pharmacology*
D005452:Fluoresceins; D005456:Fluorescent Dyes; D010446:Peptide Fragments; D018009:Receptors, Glycine; D017981:Receptors, Neurotransmitter; D013388:Succinimides; D013861:Thiocyanates; C015752:N-chlorosuccinimide; D013331:Strychnine; D016650:Fluorescein-5-isothiocyanate; D008239:Lysine; D005998:Glycine