5ds4

Crystal structure the Escherichia coli Cas1-Cas2 complex bound to protospacer DNA

spinqualitylabelsall models 5ds4, resolution 3.20Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5ds4 is a 8 chain structure with sequence from Escherichia coli K-12 and Escherichia virus M13. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 3.2Å Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function CAS2_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). Functions as a ssRNA-specific endoribonuclease (By similarity). Publication Abstract from PubMed Bacteria and archaea generate adaptive immunity against phages and plasmids by integrating foreign DNA of specific 30-40-base-pair lengths into clustered regularly interspaced short palindromic repeat (CRISPR) loci as spacer segments. The universally conserved Cas1-Cas2 integrase complex catalyses spacer acquisition using a direct nucleophilic integration mechanism similar to retroviral integrases and transposases. How the Cas1-Cas2 complex selects foreign DNA substrates for integration remains unknown. Here we present X-ray crystal structures of the Escherichia coli Cas1-Cas2 complex bound to cognate 33-nucleotide protospacer DNA substrates. The protein complex creates a curved binding surface spanning the length of the DNA and splays the ends of the protospacer to allow each terminal nucleophilic 3'-OH to enter a channel leading into the Cas1 active sites. Phosphodiester backbone interactions between the protospacer and the proteins explain the sequence-nonspecific substrate selection observed in vivo. Our results uncover the structural basis for foreign DNA capture and the mechanism by which Cas1-Cas2 functions as a molecular ruler to dictate the sequence architecture of CRISPR loci. Foreign DNA capture during CRISPR-Cas adaptive immunity.,Nunez JK, Harrington LB, Kranzusch PJ, Engelman AN, Doudna JA Nature. 2015 Nov 26;527(7579):535-8. doi: 10.1038/nature15760. Epub 2015 Oct 21. PMID:26503043 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Endonuclease 3D structures

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