8rot

Cryo-EM structure of the transmembrane anti-sigma factor DdvA

spinqualitylabelsall models 8rot, resolution 3.11Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 8rot is a 2 chain structure with sequence from Myxococcus xanthus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Electron Microscopy, Resolution 3.11Å Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q1CW22_MYXXD Publication Abstract from PubMed How CRISPR-Cas and cyclic oligonucleotide-based antiphage signaling systems (CBASS) are coordinately deployed against invaders remains unclear. We show that a locus containing two CBASS and one type III-B CRISPR-Cas system, regulated by the transmembrane anti-sigma DdvA and its cognate extracytoplasmic function (ECF) sigma DdvS, can defend Myxococcus xanthus against a phage. Cryo-electron microscopy reveals DdvA-DdvS pairs assemble as arrow-shaped transmembrane dimers. Each DdvA periplasmic domain adopts a separase/craspase-type tetratricopeptide repeat (TPR)-caspase HetF-associated with TPR (TPR-CHAT) architecture with an incomplete His-Cys active site, lacking three alpha-helices conserved among CHAT domains. Each active site faces the dimer interface, raising the possibility that signal-induced caspase-like DdvA autoproteolysis in trans precedes RseP-mediated intramembrane proteolysis and DdvS release. Nuclear magnetic resonance reveals a DdvA cytoplasmic CHCC-type zinc-bound three-helix bundle that binds to DdvS sigma(2) and sigma(4) domains, undergoing sigma(4)-induced helix extension to trap DdvS. Altogether, we provide structural-mechanistic insights into membrane anti-sigma-ECF sigma regulation of an antiviral CBASS-CRISPR-Cas defense island. Structural basis for regulation of a CBASS-CRISPR-Cas defense island by a transmembrane anti-sigma factor and its ECF sigma partner.,Bernal-Bernal D, Pantoja-Uceda D, Lopez-Alonso JP, Lopez-Rojo A, Lopez-Ruiz JA, Galbis-Martinez M, Ochoa-Lizarralde B, Tascon I, Elias-Arnanz M, Ubarretxena-Belandia I, Padmanabhan S Sci Adv. 2024 Oct 25;10(43):eadp1053. doi: 10.1126/sciadv.adp1053. Epub 2024 Oct , 25. PMID:39454004 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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