Description

IPR002156 is a Ribonuclease H domain.

<p>This entry represents the RNase H type-I domain.</p> <p>Ribonuclease H (RNase H) ([ec:3.1.26.4]) is a member of the ribonuclease family, which recognises and cleaves the RNA strand of RNA-DNA heteroduplexes. The enzyme is widely present in all three kingdoms of living organisms, including bacteria, archaea, and eukaryotes, and their counterpart domains are also found in reverse transcriptases (RTs) from retroviruses and retroelements [[cite:PUB00100891]]. RNases H are classified into two evolutionarily unrelated families, type-I and type-II RNase H, with common structural features of the catalytic domain but different range of substrates for enzymatic cleavage. There appears to be three evolutionarily distinct lineages of cellular Rnase H enzymes [[cite:PUB00081183]]. Type-I or RNase HI domains have been found in all Eukarya, one Archaea, many Eubacteria, a few non-LTR retroposons and all LTR retrotransposons. Type II enzymes consist of RNase HII (rnhB) and HIII (rnhC), which are homologous enzymes. RNase HII can be found in Archaea, Eubacteria and all Eukarya, while RNase HIII appears only in some Eubacteria. In eukaryotes and all Archaea, RNase HII enzymes may constitute the bulk of all Rnase H activity, while the reverse is true in Eubacteria like E. coli where RNase HI is the major source of RNH activity [[cite:PUB00006422], [cite:PUB00079405], [cite:PUB00025090]]. All LTR retrotransposons acquired an enzymatically weak RNase H domain that is missing an important catalytic residue found in all other RNase H enzymes. Vertebrate retroviruses appear to have reacquired their RNase H domains, which are catalytically more active, but their ancestral RNase H domains (found in other LTR retrotransposons) have degenerated to give rise to the tether domain unique to vertebrate retrovirus [[cite:PUB00096386]]. Reverse transcriptase (RT) is a modular enzyme carrying polymerase and ribonuclease H (RNase H) activities in separable domains. Retroviral RNase H is synthesised as part of the POL polyprotein that contains an aspartyl protease, a reverse transcriptase, RNase H and integrase. POL polyprotein undergoes specific enzymatic cleavage to yield the mature proteins.</p>

This description is obtained from EB-eye REST.

Associated GO terms

GO predictions are based solely on the InterPro-to-GO mappings published by EMBL-EBI, which are in turn based on the mapping of predicted domains to the InterPro dataset. The InterPro-to-GO mapping was last updated on April 27, 2020, while the GO metadata was last updated on April 27, 2020.

Associated Lotus transcripts 404