title: Modification of a specific ribosomal protein catalyzed by leucyl, phenylalanyl-tRNA: protein transferase.
abstract: Escherichia coli ribosomes washed with 1 M NH(4)Cl were found to function as acceptor for leucine and phenylalanine in the reaction catalyzed by leucyl, phenylalanyl-tRNA:protein transferase. When isolated subunits were acylated with [(14)C]phenylalanine and reisolated by gradient centrifugation, the recovered 30S particles had a specific radioactivity nearly 30 times that of similarly treated 50S particles. Autoradiography of gels, which contained protein from acylated 30S particles, that had been subjected to electrophoresis in 8 M urea and in sodium dodecyl sulfate, suggested that acceptor activity was largely due to a single protein with a molecular weight of about 12,000. Leucine and phenylalanine residues that had been transferred to ribosomal protein were reactive with fluorodinitrobenzene and were released as leucyl- or phenylalanylarginine after treatment with trypsin. The results indicate that leucyl, phenylalanyl-tRNA: protein transferase catalyzes the addition of these amino acids to an NH(2)-terminal arginine residue of a specific ribosomal protein on the 30S subunit.
mesh_terms: D000217:Acyltransferases / Q000378:metabolism*; D001345:Autoradiography; D001426:Bacterial Proteins / Q000378:metabolism*; D002247:Carbon Isotopes; D002384:Catalysis; D002499:Centrifugation, Density Gradient; D004589:Electrophoresis, Disc; D004926:Escherichia coli / Q000378:metabolism; D007930:Leucine / Q000378:metabolism*; D008970:Molecular Weight; D010649:Phenylalanine / Q000378:metabolism*; D012343:RNA, Transfer / Q000378:metabolism; D012270:Ribosomes / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D002247:Carbon Isotopes; D010649:Phenylalanine; D012343:RNA, Transfer; D000217:Acyltransferases; D007930:Leucine