The domain within your query sequence starts at position 655 and ends at position 873; the E-value for the Endonuclease_NS domain shown below is 5.33e-15.
A family of bacterial and eukaryotic endonucleases share the following characteristics: they act on both DNA and RNA, cleave double-stranded and single-stranded nucleic acids and require a divalent ion such as magnesium for their activity. An histidine has been shown to be essential for the activity of the Serratia marcescens nuclease. This residue is located in a conserved region which also contains an aspartic acid residue that could be implicated in the binding of the divalent ion.
A family of bacterial and eukaryotic endonucleases EC 3.1.30 share the following characteristics: they act on both DNA and RNA, cleave double-stranded and single-stranded nucleic acids and require a divalent ion such as magnesium for their activity. A histidine has been shown [ (PUBMED:8078761) ] to be essential for the activity of the Serratia marcescens nuclease. This residue is located in a conserved region which also contains an aspartic acid residue that could be implicated in the binding of the divalent ion.
There are 13023 Endonuclease_NS domains in 12891 proteins in SMART's nrdb database.
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Evolution (species in which this domain is found)
Taxonomic distribution of proteins containing Endonuclease_NS domain.
This tree includes only several representative species. The complete taxonomic breakdown of all proteins with Endonuclease_NS domain is also avaliable.
Click on the protein counts, or double click on taxonomic names to display all proteins containing Endonuclease_NS domain in the selected taxonomic class.
Identification of catalytically relevant amino acids of the extracellularSerratia marcescens endonuclease by alignment-guided mutagenesis.
Nucleic Acids Res. 1994; 22: 3280-7
Display abstract
By sequence alignment of the extracellular Serratia marcescens nucleasewith three related nucleases we have identified seven charged amino acidresidues which are conserved in all four sequences. Six of these residuestogether with four other partially conserved His or Asp residues werechanged to alanine by site-directed PCR-mediated mutagenesis using avariant of the nuclease gene in which the coding sequence of the signalpeptide was replaced by the coding sequence for an N-terminal affinity tag[Met(His)6GlySer]. Four of the mutant proteins showed almost no reductionin nuclease activity but five displayed a 10- to 1000-fold reduction inactivity and one (His110Ala) was inactive. Based upon these results it issuggested that the S.marcescens nuclease employs a mechanism in whichHis110 acts in concert with a Mg2+ ion and three carboxylates (Asp107,Glu148 and Glu232) as well as one or two basic amino acid residues(Arg108, Arg152).
2.1 A structure of Serratia endonuclease suggests a mechanism for bindingto double-stranded DNA.
Nat Struct Biol. 1994; 1: 461-8
Display abstract
The crystal structure of Serratia endonuclease has been solved to 2.1 A bymultiple isomorphous replacement. This magnesium-dependent enzyme isequally active against single- and double-stranded DNA, as well as RNA,without any apparent base preference. The Serratia endonuclease fold isdistinct from that of other nucleases that have been solved by X-raydiffraction. The refined structure consists of a central layer containingsix antiparallel beta-strands which is flanked on one side by a helicaldomain and on the opposite side by one dominant helix and a very longcoiled loop. Electrostatic calculations reveal a strongly polarizedmolecular surface and suggest that a cleft between this long helix andloop, near His 89, may contain the active site of the enzyme.
