Molecular mechanisms of template-independent RNA polymerization by tRNA nucleotidyltransferases
نویسندگان
چکیده
The universal 3'-terminal CCA sequence of tRNA is built and/or synthesized by the CCA-adding enzyme, CTP:(ATP) tRNA nucleotidyltransferase. This RNA polymerase has no nucleic acid template, but faithfully synthesizes the defined CCA sequence on the 3'-terminus of tRNA at one time, using CTP and ATP as substrates. The mystery of CCA-addition without a nucleic acid template by unique RNA polymerases has long fascinated researchers in the field of RNA enzymology. In this review, the mechanisms of RNA polymerization by the remarkable CCA-adding enzyme and its related enzymes are presented, based on their structural features.
منابع مشابه
Geobacter sulfurreducens contains separate C- and A-adding tRNA nucleotidyltransferases and a poly(A) polymerase.
The genome of Geobacter sulfurreducens contains three genes whose sequences are quite similar to sequences encoding known members of an RNA nucleotidyltransferase superfamily that includes tRNA nucleotidyltransferases and poly(A) polymerases. Reverse transcription-PCR using G. sulfurreducens total RNA demonstrated that the genes encoding these three proteins are transcribed. These genes, encodi...
متن کاملRecognition of the tRNA-like structure in tobacco mosaic viral RNA by ATP/CTP:tRNA nucleotidyltransferases from Escherichia coli and Saccharomyces cerevisiae.
The 3'-terminal tRNA-like structure of the tobacco mosaic virus RNA interacts with ATP/CTP:tRNA nucleotidyltransferases from Escherichia coli or yeast in much the same manner as do tRNAs. Primary sites of interaction cluster near the 3' end and in the loop proposed to be analogous to the psi-loop of a tRNA. Some modified bases in the tRNA-like structure inhibit interaction with nucleotidyltrans...
متن کاملtRNA Maturation: RNA Polymerization without a Nucleic Acid Template
The CCA-adding enzyme, which builds and repairs the 3' terminal CCA sequence of tRNA, is the only RNA polymerase that can synthesize a defined nucleotide sequence without using a nucleic acid template. New cocrystal structures tell us how this remarkable enzyme works.
متن کاملSeparation of lymphocyte chromatin into template-active fractions with specificity for eukaryotic RNA polymerase II or prokaryotic RNA polymerase.
When chromatin prepared from WI-L2 lymphocytes by low salt extraction and shearing is centrifuged on a glycerol gradient, one area of the gradient yields chromatin enriched in template activity for Escherichia coli DNA-dependent RNA polymerase (EC 2.7.7.6; nucleosidetriphosphate:RNA nucleotidyltransferase) as compared to Saccharomyces cerevisiae RNA polymerase II (or B). Another area yields chr...
متن کاملFormylmethionyl-tRNA alters RNA polymerase specificity.
Escherichia coli fMet-tRNAfMet alters the pattern of promoter selection of E. coli RNA polymerase (RNA nucleotidyltransferase, nucleosidetriphosphate:RNA nucleotidyltransferase; EC 2.7.7.6), affecting RNA synthesis from the rRNA, suIII+tRNA, and lac promoters in different ways. The in vitro synthesis of the stable RNA species is selectively decreased, whereas that of lac RNA from both the wild-...
متن کامل