A top-half tDNA minihelix is a good substrate for the eubacterial CCA-adding enzyme.
The CCA-adding enzyme [ATP(CTP):tRNA nucleotidyltransferase] catalyzes the addition and regeneration of the 3'-terminal CCA sequence of tRNAs. We show that the CCA-adding enzyme will specifically add a CCA terminus to synthetic full-length tDNA and to DNA oligonucleotides corresponding to the "top half" of tRNA-the acceptor stem and TpsiC stem-loop of tRNA. CCA addition to the top half tDNA minihelices requires a 2' as well as a 3' OH at the 3' terminus of the tDNA. Addition also depends on the length of the base paired stem, and is facilitated by, but is not dependent upon, the presence of a TpsiC loop. These results provide further evidence for independent functions of the top and bottom halves of tRNA, and support the hypothesis that these two structurally distinct and functionally independent domains evolved independently.
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Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, Connecticut 06520-8024, USA.
Weiner
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Maizels
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D001483:Base Sequence; D001665:Binding Sites; D004247:DNA / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology*; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009841:Oligonucleotides / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism; D012316:RNA Nucleotidyltransferases / Q000378:metabolism*; D013379:Substrate Specificity
D009841:Oligonucleotides; D004247:DNA; D012316:RNA Nucleotidyltransferases; C023198:tRNA nucleotidyltransferase