9l9w

Structure of SPARTA in complex with guide DNA and a 19nt target DNA

spinqualitylabelsall models 9l9w, resolution 5.87Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 9l9w is a 4 chain structure with sequence from Thermoflavifilum thermophilum. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 5.87Å Ligands: MG Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function A0A1I7NFD7_9BACT Publication Abstract from PubMed Short prokaryotic Argonaute and the associated TIR-APAZ (SPARTA) proteins constitute a prokaryotic immune system, mediating RNA- or DNA-guided target single-stranded DNA (ssDNA) to activate NADase activity and induce cell death by degrading NAD+ in response to invading plasmids. Although the guide RNA-mediated targeting mechanism of SPARTA has been established, the functional role and mechanisms of guide DNA-mediated SPARTA remain poorly understood. Here, we report two crystal structures of Crenotalea thermophila SPARTA complexes with 5'-phosphorylated 21-nt guide DNA and complementary target ssDNA lengths of 15 or 20 nt. The structures demonstrate specific recognition of the 5'-OH or 3'-OH groups in target DNA by SPARTA, while not recognizing the 5'-P group in guide DNA. This suggests distinct recognition models for guide DNA and guide RNA, indicating different activation mechanisms. Furthermore, these two structures reveal disparate models for recognizing guide DNA and target DNA, providing insights into the length requirement for SPARTA activation. Structural basis of ssDNA-guided NADase activation of prokaryotic SPARTA system.,Hu R, Guo C, Liu X, Lin Y, Yang Z, Li Z, Yang Y, Ma E, Li Y, Chen J, Liu L Nucleic Acids Res. 2025 Feb 8;53(4):gkaf110. doi: 10.1093/nar/gkaf110. PMID:39997222 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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