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Endonuclease
From Proteopedia
Contents |
Function
Endonuclease (ENN) cleaves phosphodiester bond within polynucleotide chain. ENN cleaves DNA at a restriction site which is usually a 6-nucleotide palindrome. ENN is restriction site–specific. Various types of ENN differ by their mechanism of action. ENN is used in genetic engineering to make recombinant DNA. ENN requires a restriction site and a cleavage pattern. ENN-I operates on DNA with separate restriction site and cleavage pattern, while ENN-II operates on overlapping restriction site and cleavage pattern. Some ENNs are encoded within introns thus facilitating their mobility. These ENNs or inteins are designated I-ENN[1].
The Cas ENN proteins are part of CRISPR/Cas prokaryotic immune system which confers protection from foreign genetic elements like viruses. The CRISPR (Custered Regularly Interspersed Short Palindromic Repeats) are DNA loci which are found in ca. 40% of the bacteria. The CRISPR/Cas system is being used lately as gene editing tool[2]. For more details see Cas9.
See also
Relevance
Sickle cell anemia is caused by mutation in the recognition site of MstII ENN.
Disease
Mutation in UV-specific ENN causes Xeroderma pigmentosa. Mutations in tRNA-splicing ENN cause pontocerebellar hypoplasia.
3D structures of endonuclease
Updated on 19-January-2016
References
- ↑ Nishino T, Morikawa K. Structure and function of nucleases in DNA repair: shape, grip and blade of the DNA scissors. Oncogene. 2002 Dec 16;21(58):9022-32. PMID:12483517 doi:http://dx.doi.org/10.1038/sj.onc.1206135
- ↑ Horvath P, Barrangou R. CRISPR/Cas, the immune system of bacteria and archaea. Science. 2010 Jan 8;327(5962):167-70. doi: 10.1126/science.1179555. PMID:20056882 doi:http://dx.doi.org/10.1126/science.1179555
