RNase R
RNase R, or Ribonuclease R, is a 3'-->5'
in many other organisms.When a part of another larger protein has a domain that is very similar to RNase R, this is called an RNase R domain.
Role in trans-translation and ribosomal quality control
RNase R ensures translation accuracy, correct rRNA maturation and elimination of abnormal rRNAs, and is employed by the trans-translation system to break down damaged mRNAs.[3]
In Escherichia coli, RNase R is a 92 kD protein, with the characteristic capacity to degrade structured RNA substrates without displaying sequence specificity. Therefore, RNase R acts over a range of substrates, such as, ribosomal, transfer, messenger and small non-coding RNAs. RNase R is associated with ribonucleoprotein complex that contains tmRNA and SmpB, and is involved in the development of tmRNA under cold-shock.[3]
RNase R is also associated with ribosomes and participates in rRNA, or ribosomal RNA, quality control processes. RNase R has an in vitro affinity for rRNA. In several rRNA quality control pathways, RNase R behaves as a mainfactor by enhancing the removal of faulty rRNA molecules. This protein is also critical for handling rRNA precursors and for observing the ribosome integrity.[3]
RNA digestion
RNase R has two cold shock domains, an RNase catalytic domain, an S1 domain and a basic domain.[4]
Overabundance of RNase R in a cell are harmful since RNase R is more active and more effective in breaking down RNAs than the other bacterial exoribonucleases, such as
References
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