cd09279

RNAse HI family that includes archaeal, some bacterial as well as plant RNase HI

CDD entry
Member databaseCDD
CDD typedomain
Short nameRNase_HI_like
SetRNase_H_like

Description

Ribonuclease H (RNase H) is classified into two evolutionarily unrelated families, type 1 (prokaryotic RNase HI, eukaryotic RNase H1 and viral RNase H) and type 2 (prokaryotic RNase HII and HIII, and eukaryotic RNase H2). RNase H is an endonuclease that cleaves the RNA strand of an RNA/DNA hybrid in a sequence non-specific manner. RNase H is involved in DNA replication, repair and transcription. RNase H is widely present in various organisms, including bacteria, archaea and eukaryotes and most prokaryotic and eukaryotic genomes contain multiple RNase H genes. Despite the lack of amino acid sequence homology, type 1 and type 2 RNase H share a main-chain fold and steric configurations of the four acidic active-site (DEDD) residues and have the same catalytic mechanism and functions in cells. One of the important functions of RNase H is to remove Okazaki fragments during DNA replication. Most archaeal genomes contain only type 2 RNase H (RNase HII); however, a few contain RNase HI as well. Although archaeal RNase HI sequences conserve the DEDD active-site motif, they lack other common features important for catalytic function, such as the basic protrusion region. Archaeal RNase HI homologs are more closely related to retroviral RNase HI than bacterial and eukaryotic type I RNase H in enzymatic properties.
[6, 1, 3, 4, 2, 5]

References

1.Co-crystal of Escherichia coli RNase HI with Mn2+ ions reveals two divalent metals bound in the active site. Goedken ER, Marqusee S. J. Biol. Chem. 276, 7266-71, (2001). View articlePMID: 11083878

2.Structure of human RNase H1 complexed with an RNA/DNA hybrid: insight into HIV reverse transcription. Nowotny M, Gaidamakov SA, Ghirlando R, Cerritelli SM, Crouch RJ, Yang W. Mol. Cell 28, 264-76, (2007). View articlePMID: 17964265

3.Stepwise analyses of metal ions in RNase H catalysis from substrate destabilization to product release. Nowotny M, Yang W. EMBO J. 25, 1924-33, (2006). View articlePMID: 16601679

4.Crystal structures of RNase H bound to an RNA/DNA hybrid: substrate specificity and metal-dependent catalysis. Nowotny M, Gaidamakov SA, Crouch RJ, Yang W. Cell 121, 1005-16, (2005). View articlePMID: 15989951

5.Ribonuclease H. Kanaya S. FEBS J. 276, 1481, (2009). View articlePMID: 19228198

6.Ribonuclease H evolution in retrotransposable elements. Malik HS. Cytogenet Genome Res 110, 392-401, (2005). PMID: 16093691

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