DNaseIcdeoxyribonuclease I |
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SMART accession number: | SM00476 |
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Description: | Deoxyribonuclease I catalyzes the endonucleolytic cleavage of double-stranded DNA. The enzyme is secreted outside the cell and also involved in apoptosis in the nucleus. |
Interpro abstract (IPR016202): | Deoxyribonuclease I (DNase I) ( EC 3.1.21.1 ) [ (PUBMED:3713845) ] is a vertebrate enzyme which catalyzes the endonucleolytic cleavage of double-stranded DNA to 5'- phosphodinucleotide and 5'-phosphooligonucleotide end-products. DNase I is an enzyme involved in DNA degradation; it is normally secreted outside of the cell but seems to be able to gain access to the nucleus where it is involved in cell death by apoptosis [ (PUBMED:8428592) ]. As shown in the following schematic representation, DNase I is a glycoprotein of about 260 residues with two conserved disulphide bonds.
DNase I has a pH-optimum around 7.5 and requires calcium and magnesium for full activity. It causes single strand nicks in duplex DNA. A proton acceptor-donor chain composed of an histidine and a glutamic acid produce a nucleophilic hydroxyl ion from water, which cleaves the 3'-P-O bond [ (PUBMED:3352748) ]. DNase I forms a 1:1 complex with G-actin, resulting in the inhibition of DNase activity and loss of the ability of G-actin to polymerise into fibres [ (PUBMED:2395459) ]. DNase I has been used in the treatment of lung problems in patients with cystic fibrosis: here it acts by degrading DNA found in purulent lung secretions, reducing their viscosity and making it easier for the patient to breathe [ (PUBMED:2251263) ]. The sequence of DNase I is evolutionary related to that of human muscle-specific DNase-like protein and human proteins DHP1 and DHP2. However, the first disulphide bond of DNase I is not conserved in these proteins. This entry represents DNaseI and related proteins such as DNase gamma. |
GO process: | DNA catabolic process (GO:0006308) |
GO function: | deoxyribonuclease activity (GO:0004536) |
Family alignment: |
There are 2251 DNaseIc domains in 2223 proteins in SMART's nrdb database.
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