Yeast seryl-tRNA synthetase expressed in Escherichia coli recognizes bacterial serine-specific tRNAs in vivo.
The Saccharomyces cerevisiae serS gene which encodes seryl-tRNA synthetase (SerRS) was expressed in Escherichia coli from the promoter and the ribosome binding sequences contained in its own 5'-flanking region. The low level of yeast SerRS in the prokaryotic host was sufficient to permit in vivo complementation of two temperature-sensitive E. coli serS mutants at the nonpermissive temperature. Thus, yeast SerRS can aminoacylate E. coli tRNA(Ser) species in vivo. Yeast SerRS, isolated from an overexpressing E. coli strain by a rapid two-step purification on FPLC, aminoacylated E. coli tRNA with serine much more poorly (relative kcat/Km = 2 x 10(-4)) than its homologous tRNAs. DL-Serine hydroxamate, an inhibitor of E. coli SerRS, inhibits yeast SerRS in vivo and in vitro with an inhibition constant (Ki) of 2.7 mM, a value 90-fold higher than that for E. coli SerRS.
Weygand-Durasević
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Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511.
Ban
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Jahn
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Söll
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D
D000595:Amino Acid Sequence; D001483:Base Sequence; D004926:Escherichia coli / Q000235:genetics; D005816:Genetic Complementation Test; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic / Q000235:genetics; D012329:RNA, Bacterial / Q000378:metabolism*; D012362:RNA, Transfer, Ser / Q000378:metabolism*; D011994:Recombinant Proteins / Q000187:drug effects / Q000302:isolation & purification / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D012694:Serine / Q000031:analogs & derivatives / Q000494:pharmacology; D012714:Serine-tRNA Ligase / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D013379:Substrate Specificity
D012329:RNA, Bacterial; D012362:RNA, Transfer, Ser; D011994:Recombinant Proteins; C028002:serine hydroxamate; D012694:Serine; D012714:Serine-tRNA Ligase