RNase PH

Structure of the RNase PH hexamer
Ribonuclease PH
Identifiers
Symbol	RNASEPH
Other data
EC number	2.7.7.56

RNase PH is an 3'-5' exoribonuclease and 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 cofactor to cleave nucleotide-nucleotide bonds, releasing diphosphate nucleotides. The active structure of the proteins is actually a homohexameric complex, consisting of three RNase PH dimers. ^[1] RNase PH has homologues in many other organisms, which are referred to as RNase PH-like proteins. When a part of another larger protein has a domain that is very similar to RNase PH, this is called an RNase PH domain (RPD).

See also

Two highly related exoribonuclease complexes:

• Polynucleotide Phosphorylase
• Exosome complex

References

1. ^ Ishii et al. (2003). "Crystal structure of the tRNA processing enzyme RNase PH from Aquifex aeolicus". J Biol Chem. 278: 32397–404. doi:10.1074/jbc.M300639200. PMID 12746447. 

External links

• Crystal structure of Aquifex aeolicus RNase PH at the RCSB Protein Data Bank