Endonuclease

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. The Cas ENN proteins are part of CRISPR/Cas prokaryotic immune system which confers protection from foreign genetic elements like viruses. The CRISPR (Clustered 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. For more details see CRISPR type I-A (Cascade) - see CRISPR subtype I-A CRISPR type I-B (Cascade) - see CRISPR subtype I-B CRISPR type I-C (Cascade) - see CRISPR subtype I-C CRISPR type I-E (Cascade) - see CRISPR subtype I-E (CRISPR type I-F (Csy1, Csy2, Csy3) - see CRISPR subtype I-F CRISPR type III-A (Csm complex) - see CRISPR subtype III-A (Csm complex) CRISPR type II-A - see CRISPR-Cas9 CRISPR type V (Cpf1, C2c1, C2c3) - see CRISPR type V CRISPR type VI (Cas13a (previously known as C2c2), Cas13b, Cas13c, Cas13d) - see CRISPR type VI Intron-encoded ENN or homing ENN are encoded by genes with mobile, self-splicing introns. They promote the movement of DNA sequences from one chromosome location to another. See also Apurinic-Apyrimidinic Endonuclease-1 For EcoRV ENN see Student Projects for UMass Chemistry 423 Spring 2012-3 For NEI ENN see DNA repair protein human endonuclease VIII-like 1 (NEIL1). 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. Structural highlights (PDB code 1rva). 3D structures of endonuclease Endonuclease 3D structures

spinqualitylabelsall models E. coli EcoRV endonuclease dimer (magenta, green) complex with DNA, (PDB code 1rva) Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image