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Bacterial transcription is the process in which a segment of bacterial DNA is copied into a newly synthesized strand of messenger RNA (mRNA) with use of the enzyme RNA polymerase. The process occurs in three main steps: initiation, elongation, and termination; and the result is a strand of mRNA that is complementary to a single strand of DNA.
The enzyme, characterized from the archaeon Pyrococcus furiosus, the Gram-positive bacterium Eubacterium acidaminophilum and the Gram-negative bacterium Campylobacter jejuni, interacts with an extracytoplasmic substrate binding protein and mediates the import of tungstate into the cell for incorporation into tungsten-dependent enzymes.
Most glycosyltransferase enzymes form one of two folds: GT-A or GT-B. Glycosyltransferases (GTFs, Gtfs) are enzymes that establish natural glycosidic linkages.They catalyze the transfer of saccharide moieties from an activated nucleotide sugar (also known as the "glycosyl donor") to a nucleophilic glycosyl acceptor molecule, the nucleophile of which can be oxygen- carbon-, nitrogen-, or sulfur ...
RNA Polymerase II Transcription: the process of transcript elongation facilitated by disassembly of nucleosomes. RNAP from T. aquaticus pictured during elongation. Portions of the enzyme were made transparent so as to make the path of RNA and DNA more clear. The magnesium ion (yellow) is located at the enzyme active site.
Electron micrographs of stained cell-free protein synthesis reactions revealed branched assemblies in which strings of ribosomes are linked to a central DNA fibre. [27] DNA isolated from bacterial cells co-sediment with ribosomes, further supporting the conclusion that transcription and translation occur together. [26]
Some eukaryotic cells contain an enzyme with reverse transcription activity called telomerase. Telomerase carries an RNA template from which it synthesizes a telomere, a repeating sequence of DNA, to the end of linear chromosomes. It is important because every time a linear chromosome is duplicated, it is shortened.
Each enzyme is described by "EC" followed by a sequence of four numbers which represent the hierarchy of enzymatic activity (from very general to very specific). That is, the first number broadly classifies the enzyme based on its mechanism while the other digits add more and more specificity. [21] The top-level classification is:
One major challenge of using RNA-based enzymes as a therapeutic is the short half-life of the catalytic RNA molecules in the body. To combat this, the 2’ position on the ribose is modified to improve RNA stability. One area of ribozyme gene therapy has been the inhibition of RNA-based viruses.