RNase PH is a
tRNA nucleotidyltransferase, present in
archaea and
bacteria
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of prokaryotic microorganisms. Typically a few micrometr ...
, that is involved in
tRNA
Transfer RNA (abbreviated tRNA and formerly referred to as sRNA, for soluble RNA) is an adaptor molecule composed of RNA, typically 76 to 90 nucleotides in length (in eukaryotes), that serves as the physical link between the mRNA and the amino ...
processing. Contrary to hydrolytic enzymes, it is a
phosphorolytic enzyme, meaning that it uses
inorganic
In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as ''inorganic chemist ...
phosphate as a reactant to cleave nucleotide-nucleotide bonds, releasing diphosphate
nucleotides
Nucleotides are organic molecules consisting of a nucleoside and a phosphate. They serve as monomeric units of the nucleic acid polymers – deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), both of which are essential biomolecules with ...
. The active structure of the proteins is a homohexameric complex, consisting of three
ribonuclease
Ribonuclease (commonly abbreviated RNase) is a type of nuclease that catalyzes the degradation of RNA into smaller components. Ribonucleases can be divided into endoribonucleases and exoribonucleases, and comprise several sub-classes within ...
(RNase) PH dimers.
RNase PH has
homologues in many other organisms, which are referred to as RNase PH-like proteins. The part of another larger protein with a
domain that is very similar to RNase PH is called an RNase PH domain (RPD).
See also
Two highly related exoribonuclease complexes:
*
Polynucleotide phosphorylase
Polynucleotide Phosphorylase (PNPase) is a bifunctional enzyme with a phosphorolytic 3' to 5' exoribonuclease activity and a 3'-terminal oligonucleotide polymerase activity. That is, it dismantles the RNA chain starting at the 3' end and working ...
*
Exosome complex
The exosome complex (or PM/Scl complex, often just called the exosome) is a multi-protein intracellular Protein complex, complex capable of degrading various types of RNA (ribonucleic acid) molecules. Exosome complexes are found in both eukaryo ...
References
External links
Crystal structure of ''Aquifex aeolicus'' RNase PH at the RCSB Protein Data Bank
Ribonucleases
EC 2.7.7
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