Conserved Site

Deoxyribonuclease I, conservied site (IPR033125)

Short name: DNASE_I_2

Description

Deoxyribonuclease I (DNase I) (EC:3.1.21.1) [PMID: 3713845] is a vertebrate enzyme which catalyses 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 [PMID: 8428592].

As shown in the following schematic representation, DNase I is a glycoprotein of about 260 residues with two conserved disulphide bonds.

                              +-+               +--------+
                              | |               |        |
      xxxxxxxxxxxxxxxxx#xxxxxxCxCxxxxx#xxxxxxxxxCxxxxxxxxCxxxxxxxxxxxxx
                                   

'C': conserved cysteine involved in a disulphide bond.
'#': active site residue.

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 a histidine and a glutamic acid produce a nucleophilic hydroxyl ion from water, which cleaves the 3'-P-O bond [PMID: 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 [PMID: 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 [PMID: 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 the DNase I conserved site that is involved in disulphide bond formation. It has the consensus pattern G-D-F-N-A-x-C-[SAK].

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
PROSITE patterns