8RW5
Symmetry expansion of dimeric transmembrane anti-sigma factor DdvA
Summary for 8RW5
Entry DOI | 10.2210/pdb8rw5/pdb |
EMDB information | 19404 19543 |
Descriptor | CHAT domain-containing protein (1 entity in total) |
Functional Keywords | transmembrane protein, anti-sigma factor, antiviral system, tpr-chat, signaling protein |
Biological source | Myxococcus xanthus |
Total number of polymer chains | 1 |
Total formula weight | 108640.59 |
Authors | Lopez-Alonso, J.P.,Ochoa-Lizarralde, B.,Tascon, I.,Ubarretxena-Belandia, I. (deposition date: 2024-02-02, release date: 2024-11-06) |
Primary citation | Bernal-Bernal, D.,Pantoja-Uceda, D.,Lopez-Alonso, J.P.,Lopez-Rojo, A.,Lopez-Ruiz, J.A.,Galbis-Martinez, M.,Ochoa-Lizarralde, B.,Tascon, I.,Elias-Arnanz, M.,Ubarretxena-Belandia, I.,Padmanabhan, S. Structural basis for regulation of a CBASS-CRISPR-Cas defense island by a transmembrane anti-sigma factor and its ECF sigma partner. Sci Adv, 10:eadp1053-eadp1053, 2024 Cited by PubMed Abstract: 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-σ DdvA and its cognate extracytoplasmic function (ECF) σ DdvS, can defend 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 α-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 σ and σ domains, undergoing σ-induced helix extension to trap DdvS. Altogether, we provide structural-mechanistic insights into membrane anti-σ-ECF σ regulation of an antiviral CBASS-CRISPR-Cas defense island. PubMed: 39454004DOI: 10.1126/sciadv.adp1053 PDB entries with the same primary citation |
Experimental method | ELECTRON MICROSCOPY (2.94 Å) |
Structure validation
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