title: One polypeptide with two aminoacyl-tRNA synthetase activities.
abstract: The genome sequences of certain archaea do not contain recognizable cysteinyl-transfer RNA (tRNA) synthetases, which are essential for messenger RNA-encoded protein synthesis. However, a single cysteinyl-tRNA synthetase activity was detected and purified from one such organism, Methanococcus jannaschii. The amino-terminal sequence of this protein corresponded to the predicted sequence of prolyl-tRNA synthetase. Biochemical and genetic analyses indicated that this archaeal form of prolyl-tRNA synthetase can synthesize both cysteinyl-tRNA(Cys) and prolyl-tRNA(Pro). The ability of one enzyme to provide two aminoacyl-tRNAs for protein synthesis raises questions about concepts of substrate specificity in protein synthesis and may provide insights into the evolutionary origins of this process.
authors.affiliation: Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520-8114, USA.
authors.forename: C
authors.initials: C
authors.lastname: Stathopoulos
authors.forename: T
authors.initials: T
authors.lastname: Li
authors.forename: R
authors.initials: R
authors.lastname: Longman
authors.forename: U C
authors.initials: UC
authors.lastname: Vothknecht
authors.forename: H D
authors.initials: HD
authors.lastname: Becker
authors.forename: M
authors.initials: M
authors.lastname: Ibba
authors.forename: D
authors.initials: D
authors.lastname: Söll
mesh_terms: D000604:Amino Acyl-tRNA Synthetases / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D001665:Binding Sites; D003545:Cysteine / Q000378:metabolism / Q000494:pharmacology; D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development; D019143:Evolution, Molecular; D019766:Genes, Archaeal; D017017:Methanococcus / Q000201:enzymology* / Q000235:genetics; D009097:Multienzyme Complexes / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D011392:Proline / Q000378:metabolism / Q000494:pharmacology; D012346:RNA, Transfer, Amino Acyl / Q000096:biosynthesis*; D020539:Sequence Analysis, Protein; D013379:Substrate Specificity; D046249:Transfer RNA Aminoacylation; D014169:Transformation, Bacterial
chemical_list: D009097:Multienzyme Complexes; D012346:RNA, Transfer, Amino Acyl; D011392:Proline; D000604:Amino Acyl-tRNA Synthetases; C100134:prolyl T RNA synthetase; C019975:cysteinyl-tRNA synthetase; D003545:Cysteine