Cloning and sequencing of cDNA encoding the rice methionyl-tRNA synthetase

Three overlapping clones of cDNA, Mos43, Mos28 and Mos60, coding for methionyl-tRNA synthetase were obtained by screening the Oryza sativa lambda gt11 library. Their nucleotide sequence of 2850 bp was determined. The deduced amino-acid sequence of the isolated clones contains a HLGN and KFSKS motifs, which are conserved for this family of enzymes and have been proposed to be the signature sequences for class I aminoacyl-tRNA synthetases. A comparison of the rice MetRS primary structure with those deposited in EMBL/GenBank points to its high homology to yeast, human and Caenorhabditis elegans MetRSs. Interestingly, a great similarity of its C terminus to endothelial-monocyte-activating polypeptide II (EMAPII) and yeast protein G4p1 was observed.