Purification and characterization of subforms of the guanine-nucleotide-binding proteins G alpha i and G alpha o.
Five different pertussis-toxin-sensitive guanine-nucleotide-binding proteins (G proteins) were purified from bovine brain. Immunochemical characterization of alpha subunits identified two G alpha o proteins (G alpha o-I and G alpha o-II), two 41-kDa G alpha i proteins (G alpha i-I and G alpha i-II) and the 40-kDa G alpha i2 protein. Site-directed antisera specific for G alpha o proteins did not differentiate between G alpha o-I and G alpha o-II. However, in situ peptide mapping using polyacrylamide gel electrophoresis revealed distinct cleavage products with different proteases for each of these proteins. Additionally comparison of Rf values demonstrated a slightly faster migration for G alpha o-II than for G alpha o-I, which is the only type of G alpha o protein present in cell membranes of the neuroblastoma/glioma cell line NG 108-15. The importance of these structural differences and possible functional implications are discussed.
Lang
J
J
Max-Planck-Institut für Psychiatrie, Abteilung Neuropharmakologie, Martinsried.
D000818:Animals; D001921:Brain / Q000378:metabolism*; D002417:Cattle; D002852:Chromatography, Ion Exchange; D004591:Electrophoresis, Polyacrylamide Gel; D019204:GTP-Binding Proteins / Q000302:isolation & purification* / Q000378:metabolism; D007106:Immune Sera; D015151:Immunoblotting; D046911:Macromolecular Substances; D010449:Peptide Mapping; D037342:Pertussis Toxin; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D007106:Immune Sera; D046911:Macromolecular Substances; D010566:Virulence Factors, Bordetella; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins