Methionyl-tRNA synthetase from Escherichia coli. Primary structure of the active crystallised tryptic fragment.
A 3300-base segment of Escherichia coli chromosomal DNA, cloned into pBR322, will complement a methionine auxotroph in which the lesion is a defective methionyl-tRNA synthetase with a much reduced affinity for methionine. Crude extracts of these transformants contain elevated levels of a protein which has a subunit molecular weight of 66 000, methionyl-tRNA synthetase aminoacylation activity in vitro and which cross-reacts with anti-(methionyl-tRNA synthetase) antibodies. This polypeptide is very slightly larger than the well-characterised and crystallised tryptic fragment of methionyl-tRNA synthetase. A DNA sequence of 1750 residues at one end of the cloned insert codes for a non-terminated open reading frame in which we can locate a large number of methionyl-tRNA synthetase tryptic and chymotryptic peptides. We have also sequenced 300 nucleotides upstream of this coding segment where we find a large invert repeat in the putative methionyl-tRNA synthetase promoter region.
D000595:Amino Acid Sequence; D000604:Amino Acyl-tRNA Synthetases / Q000302:isolation & purification*; D001426:Bacterial Proteins / Q000302:isolation & purification; D055598:Chemical Phenomena; D002621:Chemistry; D002918:Chymotrypsin; D003001:Cloning, Molecular; D003460:Crystallization; D004269:DNA, Bacterial / Q000302:isolation & purification; D004926:Escherichia coli / Q000201:enzymology*; D008718:Methionine-tRNA Ligase / Q000235:genetics / Q000302:isolation & purification*; D010446:Peptide Fragments / Q000302:isolation & purification*; D014357:Trypsin
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D010446:Peptide Fragments; D002918:Chymotrypsin; D014357:Trypsin; D000604:Amino Acyl-tRNA Synthetases; D008718:Methionine-tRNA Ligase