Aminoacylation of Phaseolus vulgaris cytoplasmic, chloroplastic and mitochondrial tRNAsMet and of Escherichia coli tRNAsMet by homologous and heterologous enzymes.

Met-tRNA synthetase from Paseolus vulgaris cytoplasm could be separated from its chloroplastic or mitochondrial counterpart by DEAE-cellulose chromatography, but the Met-tRNA synthetase from the two latter organelles could not be distinguished using DEAE-cellulose, hydroxyapatite or CM-Sephadex chromatography. As revealed by reverse-phase chromatography, bean cytoplasm contains 2 tRNAsMet; only one is charged by chloroplast, mitochondrial or Escherichia coli Met-tRNA synthetase. Mitochondria contain, in addition to the 2 cytoplasmic tRNAsMet, 3 mitochondria-spedific tRNAsMet; 2 can be formylated by the mitochondrial or the E. coli transformylase; all 3 are charged by mitochondrial, chloroplastic or E, coli Met-tRNA synthetase; none is charged by the cytoplasmic enzyme. Chloroplasts contain, in addition to the 2 cytoplasmic tRNAsMet, 3 chloroplast-specific tRNAsMet, different from the mitochondrial tRNAsMet; one is formylatable by the chloroplastic or the E. coli transformylase; all 3 are charged by chloroplastic, mitochondrial or E. coli Met-tRNA synthetase; only one is charged by the cytoplasmic enzyme. Of the 3 E. coli tRNAsMet, only the formylatable species can be charged by bean cytoplasmic, chloroplastic or mitochondrial Met-tRNA synthetase.