6p7o

Structure of E. coli MS115-1 NucC, Apo form

spinqualitylabelsall models 6p7o, resolution 1.75Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6p7o is a 1 chain structure with sequence from Escherichia coli MS 115-1. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.752Å Ligands: CL, MG, P6G, PGE Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function NUCC_ECOM1 CBASS (cyclic oligonucleotide-based antiphage signaling system) provides immunity against bacteriophage. The CD-NTase protein synthesizes cyclic nucleotides in response to infection; these serve as specific second messenger signals. The signals activate a diverse range of effectors, leading to bacterial cell death and thus abortive phage infection. A type III-C(AAA) CBASS system (PubMed:32839535). A cyclic nucleotide-activated dsDNase. In the presence of 3',3',3'-cyclic AMP-AMP-AMP (cAAA), and to a lesser extent 3',3',3'-cyclic AMP-AMP-GMP (cAAG) and cyclic-di-AMP (c-di-AMP), endonucleolytically degrades dsDNA (PubMed:31932165, PubMed:31932164). Binds one cAAA in a pocket on one surface of the trimer; cAAA binding promotes hexamerization, which is necessary for nuclease activation. Also binds c-diAMP or linear di-AMP with lower affinity. The nuclease digests dsDNA to about 50 bp lengths with a 2-base 3' overhang and a consensus recognition site of 5'-Axx|T-3'. DNA has been modeled to contact a pair of juxtaposed active sites (one from each layer of the hexamer), accounting for cleavage on both strands and the 2-base overhang (PubMed:31932164). Protects E.coli strain JP313 against bacteriophage lambda cI- infection. When the cdnC-cap7-cap6-nucC operon is transformed into a susceptible strain it confers bacteriophage immunity. Mutations in the sensor (Cap7 also called HORMA) or effector proteins (CdnC, NucC) but not the disassembly protein (Cap6 also called Trip13) no longer confer immunity. The presence of the intact operon leads to culture collapse and cell death which occurs before the phage has finished its replication cycle, thus protecting non-infected bacteria by aborting the phage infection and preventing its propagation.

Proteopedia Page Contributors and Editors (what is this?)

OCA