title: tRNA-nucleotidyltransferases: highly unusual RNA polymerases with vital functions.
abstract: tRNA-nucleotidyltransferases are fascinating and unusual RNA polymerases responsible for the synthesis of the nucleotide triplet CCA at the 3'-terminus of tRNAs. As this CCA end represents an essential functional element for aminoacylation and translation, these polymerases (CCA-adding enzymes) are of vital importance in all organisms. With a possible origin of ancient telomerase-like activity, the CCA-adding enzymes obviously emerged twice during evolution, leading to structurally different, but functionally identical enzymes. The evolution as well as the unique polymerization features of these interesting proteins will be discussed in this review.
authors.affiliation: Institute for Biochemistry, University of Leipzig, Brüderstr. 34, 04103 Leipzig, Germany. svoertler@uni-leipzig.de
authors.forename: Stefan
authors.initials: S
authors.lastname: Vörtler
authors.forename: Mario
authors.initials: M
authors.lastname: Mörl
mesh_terms: D012321:DNA-Directed RNA Polymerases / Q000737:chemistry / Q000145:classification / Q000378:metabolism*; D019143:Evolution, Molecular; D011487:Protein Conformation; D012316:RNA Nucleotidyltransferases / Q000737:chemistry / Q000145:classification / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: D012316:RNA Nucleotidyltransferases; D012321:DNA-Directed RNA Polymerases