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344  structures 3870  species 3  interactions 16967  sequences 181  architectures

Family: RNase_H (PF00075)

Summary: RNase H

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RNase H Provide feedback

RNase H digests the RNA strand of an RNA/DNA hybrid. Important enzyme in retroviral replication cycle, and often found as a domain associated with reverse transcriptases. Structure is a mixed alpha+beta fold with three a/b/a layers.

Internal database links

External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR002156

The RNase H domain is responsible for hydrolysis of the RNA portion of RNA x DNA hybrids, and this activity requires the presence of divalent cations (Mg2+ or Mn2+) that bind its active site. This domain is a part of a large family of homologous RNase H enzymes of which the RNase HI protein from Escherichia coli is the best characterised [PUBMED:9741851]. Secondary structure predictions for the enzymes from E. coli, yeast, human liver and diverse retroviruses (such as Rous sarcoma virus and the Foamy viruses) supported, in every case, the five beta-strands (1 to 5) and four or five alpha-helices (A, B/C, D, E) that have been identified by crystallography in the RNase H domain of Human immunodeficiency virus 1 (HIV-1) reverse transcriptase and in E. coli RNase H [PUBMED:10603172]. Reverse transcriptase (RT) is a modular enzyme carrying polymerase and ribonuclease H (RNase H) activities in separable domains. Reverse transcriptase (RT) converts the single-stranded RNA genome of a retrovirus into a double-stranded DNA copy for integration into the host genome. This process requires ribonuclease H as well as RNA- and DNA-directed DNA polymerase activities.

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. Bacterial RNase H EC catalyses endonucleolytic cleavage to 5'-phosphomonoester acting on RNA-DNA hybrids.

The 3D structure of the RNase H domain from diverse bacteria and retroviruses has been solved [PUBMED:2169648, PUBMED:8108376, PUBMED:1707186]. All have four beta strands and four to five alpha helices. The E. coli RNase H1 protein binds a single Mg2+ ion cofactor in the active site of the enzyme. The divalent cation is bound by the carboxyl groups of four acidic residues, Asp-10, Glu-48, Asp-70, and Asp-134 [PUBMED:8108376]. The first three acidic residues are highly conserved in all bacterial and retroviral RNase H sequences.

Gene Ontology

The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.

Domain organisation

Below is a listing of the unique domain organisations or architectures in which this domain is found. More...

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Alignments

We store a range of different sequence alignments for families. As well as the seed alignment from which the family is built, we provide the full alignment, generated by searching the sequence database using the family HMM. We also generate alignments using four representative proteomes (RP) sets, the NCBI sequence database, and our metagenomics sequence database. More...

View options

We make a range of alignments for each Pfam-A family. You can see a description of each above. You can view these alignments in various ways but please note that some types of alignment are never generated while others may not be available for all families, most commonly because the alignments are too large to handle.

  Seed
(65)
Full
(16967)
Representative proteomes NCBI
(16858)
Meta
(2641)
RP15
(638)
RP35
(1217)
RP55
(1694)
RP75
(1941)
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1Cannot generate PP/Heatmap alignments for seeds; no PP data available

Key: ✓ available, x not generated, not available.

Format an alignment

  Seed
(65)
Full
(16967)
Representative proteomes NCBI
(16858)
Meta
(2641)
RP15
(638)
RP35
(1217)
RP55
(1694)
RP75
(1941)
Alignment:
Format:
Order:
Sequence:
Gaps:
Download/view:

Download options

We make all of our alignments available in Stockholm format. You can download them here as raw, plain text files or as gzip-compressed files.

  Seed
(65)
Full
(16967)
Representative proteomes NCBI
(16858)
Meta
(2641)
RP15
(638)
RP35
(1217)
RP55
(1694)
RP75
(1941)
Raw Stockholm Download   Download   Download   Download   Download   Download   Download   Download  
Gzipped Download   Download   Download   Download   Download   Download   Download   Download  

You can also download a FASTA format file containing the full-length sequences for all sequences in the full alignment.

External links

MyHits provides a collection of tools to handle multiple sequence alignments. For example, one can refine a seed alignment (sequence addition or removal, re-alignment or manual edition) and then search databases for remote homologs using HMMER3.

HMM logo

HMM logos is one way of visualising profile HMMs. Logos provide a quick overview of the properties of an HMM in a graphical form. You can see a more detailed description of HMM logos and find out how you can interpret them here. More...

Trees

This page displays the phylogenetic tree for this family's seed alignment. We use FastTree to calculate neighbour join trees with a local bootstrap based on 100 resamples (shown next to the tree nodes). FastTree calculates approximately-maximum-likelihood phylogenetic trees from our seed alignment.

Note: You can also download the data file for the tree.

Curation and family details

This section shows the detailed information about the Pfam family. You can see the definitions of many of the terms in this section in the glossary and a fuller explanation of the scoring system that we use in the scores section of the help pages.

Curation View help on the curation process

Seed source: Swissprot; SCOP and HMM_iterative_training
Previous IDs: rnaseH; RnaseH;
Type: Domain
Author: Eddy SR
Number in seed: 65
Number in full: 16967
Average length of the domain: 121.40 aa
Average identity of full alignment: 50 %
Average coverage of the sequence by the domain: 20.38 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 23193494 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 21.3 21.3
Trusted cut-off 21.3 21.3
Noise cut-off 21.2 21.2
Model length: 132
Family (HMM) version: 19
Download: download the raw HMM for this family

Species distribution

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This visualisation provides a simple graphical representation of the distribution of this family across species. You can find the original interactive tree in the adjacent tab. More...

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Interactions

There are 3 interactions for this family. More...

RVT_connect RNase_H RVT_thumb

Structures

For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the RNase_H domain has been found. There are 344 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein seqence.

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