Degradosome
Even in resting cells, RNA is degraded in a steady state, and the nucleotide products of this process are later reused for fresh rounds of nucleic acid synthesis.
The RNA degradosome was discovered in two different laboratories while they were working on the purification and characterization of E. coli, RNase E and the factors that could have an influence on the activity of the RNA-degrading enzymes, concretely, PNPase.
Supplementary alternate degradosome components are PcnB (poly A polymerase) and the RNA helicases RhlE and SrmB.
Additional alternate degradosome components during stationary phase include Rnr (RNase R) and the putative RNA helicase HrpA.
Looking into the steps of the degradation of a transcript in E. coli, what is known is that in the first place the endoribonucleases can cleave the substrates so that later the exoribonucleases can work on the products.
[8][9] One particularly intriguing aspect of the bacterial RNA degradosome is the presence of metabolic enzymes in many of the studied complexes.
This multi-protein complex is stimulated by a non-coding RNA, called miRNA in Eukaryotic cells and sRNA in bacteria.
This way, the ribosomes can do their job of decoding, process that stops when they arrive to the complex, where all the destruction procedure is switched on.
If there are any secondary structures, the performance of polymerase PAP is needed to simplify the reduction by exoribonucleases such as PNPase.
[5] The degradosome, which is dynamic in conformation, variable in composition and non-essential under determined laboratory conditions, has nevertheless been maintained throughout the evolution of many bacterial species (Archaea, Eukaryote, Escherichia coli, Mitochondria, etc.
It is one of the most studied organisms at laboratories and it has been a useful model for understanding genetic regulation in bacteria and other domains of life.
It shares homologous components and functional analogy with similar assemblies found in all domains of life.
One of its components is an ATP-dependent motor that is activated through protein-protein interactions and cooperates with the ribonucleases in an energy-dependent mode of RNA degradation.
