title: Aminoacyl-tRNA formation in the extreme thermophile Thermus thermophilus.
abstract: Thermophilic organisms must be capable of accurate translation at temperatures in which the individual components of the translation machinery and also specific amino acids are particularly sensitive. Thermus thermophilus is a good model organism for studies of thermophilic translation because many of the components in this process have undergone structural and biochemical characterization. We have focused on the pathways of aminoacyl-tRNA synthesis for glutamine, asparagine, proline, and cysteine. We show that the T. thermophilus prolyl-tRNA synthetase (ProRS) exhibits cysteinyl-tRNA synthetase (CysRS) activity although the organism also encodes a canonical CysRS. The ProRS requires tRNA for cysteine activation, as is known for the characterized archaeal prolyl-cysteinyl-tRNA synthetase (ProCysRS) enzymes. The heterotrimeric T. thermophilus aspartyl-tRNA(Asn) amidotransferase can form Gln-tRNA in addition to Asn-tRNA: however, a 13-amino-acid C-terminal truncation of the holoenzyme A subunit is deficient in both activities when assayed with homologous substrates. A survey of codon usage in completed prokaryotic genomes identified a higher Glu:Gln ratio in proteins of thermophiles compared to mesophiles.
authors.affiliation: Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520-8114, USA.
authors.forename: Liang
authors.initials: L
authors.lastname: Feng
authors.forename: Constantinos
authors.initials: C
authors.lastname: Stathopoulos
authors.forename: Ivan
authors.initials: I
authors.lastname: Ahel
authors.forename: Anusri
authors.initials: A
authors.lastname: Mitra
authors.forename: Debra
authors.initials: D
authors.lastname: Tumbula-Hansen
authors.forename: Thomas
authors.initials: T
authors.lastname: Hartsch
authors.forename: Dieter
authors.initials: D
authors.lastname: Söll
mesh_terms: D000604:Amino Acyl-tRNA Synthetases / Q000378:metabolism; D001226:Aspartate-tRNA Ligase; D001483:Base Sequence; D003062:Codon / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D019143:Evolution, Molecular; D008969:Molecular Sequence Data; D019884:Nitrogenous Group Transferases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D014176:Protein Biosynthesis; D012329:RNA, Bacterial / Q000096:biosynthesis*; D012346:RNA, Transfer, Amino Acyl / Q000096:biosynthesis*; D017384:Sequence Deletion; D013696:Temperature; D016963:Thermus thermophilus / Q000235:genetics / Q000378:metabolism*
chemical_list: D003062:Codon; D004269:DNA, Bacterial; D012329:RNA, Bacterial; D012346:RNA, Transfer, Amino Acyl; C412016:Asp-tRNA(Asn) amidotransferase; D019884:Nitrogenous Group Transferases; D000604:Amino Acyl-tRNA Synthetases; D001226:Aspartate-tRNA Ligase; C100134:prolyl T RNA synthetase; C029194:asparaginyl-tRNA synthetase