8VX9
Structure of HamAB apo complex from the Escherichia coli Hachiman defense system
Summary for 8VX9
| Entry DOI | 10.2210/pdb8vx9/pdb |
| EMDB information | 43613 |
| Descriptor | HamA, HamB (2 entities in total) |
| Functional Keywords | nuclease-helicase complex, antiphage defense system, immune system |
| Biological source | Escherichia coli More |
| Total number of polymer chains | 2 |
| Total formula weight | 159822.25 |
| Authors | Tuck, O.T.,Doudna, J.A. (deposition date: 2024-02-03, release date: 2024-03-13, Last modification date: 2024-03-20) |
| Primary citation | Tuck, O.T.,Adler, B.A.,Armbruster, E.G.,Lahiri, A.,Hu, J.J.,Zhou, J.,Pogliano, J.,Doudna, J.A. Hachiman is a genome integrity sensor. Biorxiv, 2024 Cited by PubMed Abstract: Hachiman is a broad-spectrum antiphage defense system of unknown function. We show here that Hachiman comprises a heterodimeric nuclease-helicase complex, HamAB. HamA, previously a protein of unknown function, is the effector nuclease. HamB is the sensor helicase. HamB constrains HamA activity during surveillance of intact dsDNA. When the HamAB complex detects DNA damage, HamB helicase activity liberates HamA, unleashing nuclease activity. Hachiman activation degrades all DNA in the cell, creating 'phantom' cells devoid of both phage and host DNA. We demonstrate Hachiman activation in the absence of phage by treatment with DNA-damaging agents, suggesting that Hachiman responds to aberrant DNA states. Phylogenetic similarities between the Hachiman helicase and eukaryotic enzymes suggest this bacterial immune system has been repurposed for diverse functions across all domains of life. PubMed: 38464307DOI: 10.1101/2024.02.29.582594 PDB entries with the same primary citation |
| Experimental method | ELECTRON MICROSCOPY (2.65 Å) |
Structure validation
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