5vvj

Cas1-Cas2 bound to half-site intermediate

spinqualitylabelsall models 5vvj, resolution 3.89Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5vvj is a 8 chain structure with sequence from Escherichia coli K-12 and Synthetic construct. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 3.89Å Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function CAS1_ECOLI CRISPR (clustered regularly interspaced short palindromic repeat), is an adaptive immune system that provides protection against mobile genetic elements (viruses, transposable elements and conjugative plasmids). CRISPR clusters contain sequences complementary to antecedent mobile elements and target invading nucleic acids. CRISPR clusters are transcribed and processed into CRISPR RNA (crRNA). Cas1 is thought to be involved in CRISPR adaptation, the first stage of CRISPR immunity. Might be involved in the addition/removal of CRISPR spacers. Endonucleolytically cleaves linear ssRNA, ssDNA and short (34 base) dsDNA as well as branched DNA substrates such as Holliday junctions, replication forks and 5'-flap DNA substrates. Genetic interactions suggest Cas1 interacts with components of the RecBC and RuvB DNA repair systems. Publication Abstract from PubMed CRISPR-Cas systems depend on the Cas1-Cas2 integrase to capture and integrate short foreign DNA fragments into the CRISPR locus, enabling adaptation to new viruses. We present crystal structures of Cas1-Cas2 bound to both donor and target DNA in intermediate and product integration complexes, as well as a cryo-electron microscopy structure of the full CRISPR locus integration complex including the accessory protein Integration Host Factor (IHF). The structures show unexpectedly that indirect sequence recognition dictates integration site selection by favoring deformation of the repeat and the flanking sequences. IHF binding bends the DNA sharply, bringing an upstream recognition motif into contact with Cas1 to increase both the specificity and efficiency of integration. These results explain how the Cas1-Cas2 CRISPR integrase recognizes a sequence-dependent DNA structure to ensure site-selective CRISPR array expansion during the initial step of bacterial adaptive immunity. Structures of the CRISPR genome integration complex.,Wright AV, Liu JJ, Knott GJ, Doxzen KW, Nogales E, Doudna JA Science. 2017 Jul 20. pii: eaao0679. doi: 10.1126/science.aao0679. PMID:28729350 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Endonuclease 3D structures

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