One polypeptide with two aminoacyl-tRNA synthetase activities.
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.
Stathopoulos
C
C
Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520-8114, USA.
Li
T
T
Longman
R
R
Vothknecht
U C
UC
Becker
H D
HD
Ibba
M
M
Söll
D
D
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
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