RNase PH is a tRNA nucleotidyltransferase, present in archaea and bacteria, that is involved in tRNA processing. Contrary to hydrolytic enzymes, it is a phosphorolytic enzyme, meaning that it uses inorganic phosphate as a reactant to cleave nucleotide-nucleotide bonds, releasing diphosphate nucleotides. The active structure of the proteins is a homohexameric complex, consisting of three ribonuclease (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).
Structure of the RNase PH hexamer
Two highly related exoribonuclease complexes:
- Ishii R, Nureki O, Yokoyama S (August 2003). "Crystal structure of the tRNA processing enzyme RNase PH from Aquifex aeolicus". The Journal of Biological Chemistry. 278 (34): 32397–404. doi:10.1074/jbc.M300639200. PMID 12746447.
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