A eubacterial Mycobacterium tuberculosis tRNA synthetase is eukaryote-like and resistant to a eubacterial-specific antisynthetase drug.

Abstract

We report here the cloning and primary structure of Mycobacterium tuberculosis isoleucyl-tRNA synthetase. The predicted 1035-amino acid protein is significantly more similar in sequence to eukaryote cytoplasmic than to other eubacterial isoleucyl-tRNA synthetases. This similarity correlates with the enzyme being resistant to pseudomonic acid A, a potent inhibitor of Escherichia coli and other eubacterial isoleucyl-tRNA synthetases, but not of eukaryote cytoplasmic enzymes. Consistent with its eukaryote-like features, and unlike E. coli isoleucyl-tRNA synthetase, the M. tuberculosis enzyme charged yeast isoleucine tRNA. In spite of these eukaryote-like features, M. tuberculosis isoleucyl-tRNA synthetase exhibited highly specific cross-species aminoacylation, as demonstrated by its ability to complement isoleucyl-tRNA synthetase-deficient mutants of E. coli. When introduced into a pseudomonic acid-sensitive wild-type strain of E. coli, the M. tuberculosis enzyme conferred trans-dominant resistance to the drug. The results demonstrate that the sequence of a tRNA synthetase could have predictive value with respect to the interaction of that synthetase with a specific inhibitor. The results also demonstrate that mobilization of a pathogen's gene for a drug-resistant protein target can spread resistance to other, normally drug-sensitive pathogens infecting the same host.

• Authors: M Sassanfar, J E Kranz, P Gallant, P Schimmel, K Shiba
• Journal: Biochemistry (Biochemistry) Vol. 35 Issue 31 Pg. 9995-10003 (Aug 06 1996) ISSN: 0006-2960 [Print] United States
• PMID: 8756461 (Publication Type: Comparative Study, Journal Article, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• DNA Primers
• Recombinant Proteins
• Isoleucine-tRNA Ligase

Topics

• Amino Acid Sequence
• Archaea (enzymology, genetics)
• Base Sequence
• Cloning, Molecular
• DNA Primers
• Escherichia coli
• Eubacterium (enzymology, genetics)
• Isoleucine-tRNA Ligase (biosynthesis, chemistry, metabolism)
• Kinetics
• Molecular Sequence Data
• Mutagenesis, Site-Directed
• Mycobacterium tuberculosis (enzymology, genetics)
• Phylogeny
• Polymerase Chain Reaction
• Protein Folding
• Recombinant Proteins (biosynthesis, chemistry, metabolism)
• Sequence Homology, Amino Acid