8tjy

Structure of Gabija AB complex

spinqualitylabelsall models 8tjy, resolution 2.79Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 8tjy is a 8 chain structure with sequence from Bacillus cereus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Electron Microscopy, Resolution 2.79Å Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function GAJA_BACC6 Component of antiviral defense system Gabija type I, composed of GajA and GajB (PubMed:29371424). Endonuclease that nicks double-stranded DNA within the sequence 5'-TNNNCGGGNNA-3' in the absence of nucleotides (NTP, dNTP and NDPs), cleaving after C-1 (PubMed:33885789, PubMed:37992757). Has no detected ATPase activity (PubMed:33885789). Expression of Gabija type I in B.subtilis (strain BEST7003) confers resistance to phages phi105, phi29, rho14, SpBeta and SBSphiC (PubMed:29371424). Expression of Gabija type I in E.coli B (strain ATCC 11303) confers resistance to phage T7 (PubMed:33885789). It is thought that this enzyme is strongly suppressed during physiological growth (in E.coli total nucleotide concentration is over 8.7 mM in mid-log phase), but during viral replication, when nucleotides are rapidly consumed, it is de-suppressed and degrades target DNA (Probable). Publication Abstract from PubMed As one of the most prevalent anti-phage defense systems in prokaryotes, Gabija consists of a Gabija protein A (GajA) and a Gabija protein B (GajB). The assembly and function of the Gabija system remain unclear. Here we present cryo-EM structures of Bacillus cereus GajA and GajAB complex, revealing tetrameric and octameric assemblies, respectively. In the center of the complex, GajA assembles into a tetramer, which recruits two sets of GajB dimer at opposite sides of the complex, resulting in a 4:4 GajAB supramolecular complex for anti-phage defense. Further biochemical analysis showed that GajA alone is sufficient to cut double-stranded DNA and plasmid DNA, which can be inhibited by ATP. Unexpectedly, the GajAB displays enhanced activity for plasmid DNA, suggesting a role of substrate selection by GajB. Together, our study defines a framework for understanding anti-phage immune defense by the GajAB complex. Molecular basis of Gabija anti-phage supramolecular assemblies.,Yang XY, Shen Z, Xie J, Greenwald J, Marathe I, Lin Q, Xie WJ, Wysocki VH, Fu TM Nat Struct Mol Biol. 2024 Aug;31(8):1243-1250. doi: 10.1038/s41594-024-01283-w. , Epub 2024 Apr 16. PMID:38627580 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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