Identification of two tRNA thiolation genes required for cell growth at extremely high temperatures.
Thermostability of tRNA in thermophilic bacteria is effected by post-transcriptional modifications, such as 2-thioribothymidine (s2T) at position 54. Using a proteomics approach, we identified two genes (ttuA and ttuB; tRNA-two-thiouridine) that are essential for the synthesis of s2T in Thermus thermophilus. Mutation of either gene completely abolishes thio-modification of s2T, and these mutants exhibit a temperature-sensitive phenotype. These results suggest that bacterial growth at higher temperatures is achieved through the thermal stabilization of tRNA by a 2-thiolation modification. TtuA (TTC0106) is possibly an ATPase possessing a P-loop motif. TtuB (TTC0105) is a putative thio-carrier protein that exhibits significant sequence homology with ThiS of the thiamine synthesis pathway. Both TtuA and TtuB are required for in vitro s2T formation in the presence of cysteine and ATP. The addition of cysteine desulfurases such as IscS (TTC0087) or SufS (TTC1373) enhances the sulfur transfer reaction in vitro.
Biological Information Research Center, National Institute of Advanced Industrial Science and Technology, 2-42 Aomi, Koto-ku, Tokyo 135-0064, Japan.
Naoki
N
Shigi
Yuriko
Y
Sakaguchi
Tsutomu
T
Suzuki
Kimitsuna
K
Watanabe
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001483:Base Sequence; D002352:Carrier Proteins / Q000737:chemistry; D049109:Cell Proliferation; D029968:Escherichia coli Proteins / Q000737:chemistry; D006358:Hot Temperature; D008969:Molecular Sequence Data; D009154:Mutation; D009690:Nucleic Acid Conformation; D010641:Phenotype; D012343:RNA, Transfer / Q000737:chemistry*; D011994:Recombinant Proteins / Q000737:chemistry; D017386:Sequence Homology, Amino Acid; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D016963:Thermus thermophilus / Q000378:metabolism
D002352:Carrier Proteins; D029968:Escherichia coli Proteins; D011994:Recombinant Proteins; D013438:Sulfhydryl Compounds; C411655:thiS protein, E coli; D012343:RNA, Transfer