title: tRNA2Thr complements temperature sensitivity caused by null mutations in the htrB gene in Escherichia coli.
abstract: According to the wobble rule, tRNA2Thr is nonessential for protein synthesis, because the codon (ACG) that is recognized by tRNA2Thr is also recognized by tRNA4Thr. In order to investigate the reason that this nonessential tRNA nevertheless exists in Escherichia coli, we attempted to isolate tRNA2Thr-requiring mutants. Using strain JM101F(-), which lacks the gene for tRNA2Thr, we succeeded in isolating two temperature-sensitive mutants whose temperature sensitivity was complemented by introduction of the gene for tRNA2Thr. These mutants had a mutation in the htrB gene, whose product is an enzyme involved in lipid A biosynthesis. Although it is known that some null mutations in the htrB gene give a temperature-sensitive phenotype, our mutants exhibited tighter temperature sensitivity. We discuss a possible mechanism for the requirement for tRNA2Thr.
authors.affiliation: Department of Biophysics, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan.
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Mohri
authors.forename: Simon
authors.initials: S
authors.lastname: Goto
authors.forename: Kenji
authors.initials: K
authors.lastname: Nakahigashi
authors.forename: Hachiro
authors.initials: H
authors.lastname: Inokuchi
mesh_terms: D000217:Acyltransferases; D000926:Anticodon; D001426:Bacterial Proteins; D004926:Escherichia coli / Q000502:physiology*; D029968:Escherichia coli Proteins / Q000235:genetics* / Q000378:metabolism; D008050:Lipid A / Q000096:biosynthesis; D009154:Mutation; D012363:RNA, Transfer, Thr; D013696:Temperature
chemical_list: D000926:Anticodon; D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D008050:Lipid A; D012363:RNA, Transfer, Thr; D000217:Acyltransferases; C492237:LpxL protein, E coli; C118473:LpxL protein, bacteria