9GTR
Cryo-EM structure of a contractile injection system in Streptomyces coelicolor, the baseplate complex in extended state applied 3-fold symmetry.
This is a non-PDB format compatible entry.
Summary for 9GTR
| Entry DOI | 10.2210/pdb9gtr/pdb |
| EMDB information | 51565 |
| Descriptor | Gp5/Type VI secretion system Vgr protein OB-fold domain-containing protein (1 entity in total) |
| Functional Keywords | contractile injection system, structural protein |
| Biological source | Streptomyces coelicolor A3(2) |
| Total number of polymer chains | 3 |
| Total formula weight | 204485.86 |
| Authors | Casu, B.,Sallmen, J.W.,Hass, P.E.,Afanasyev, P.,Xu, J.,Schlimpert, S.,Pilhofer, M. (deposition date: 2024-09-18, release date: 2025-06-18, Last modification date: 2025-07-16) |
| Primary citation | Casu, B.,Sallmen, J.W.,Haas, P.E.,Chandra, G.,Afanasyev, P.,Xu, J.,Pilhofer, M.,Schlimpert, S. Function and firing of the Streptomyces coelicolor contractile injection system requires the membrane protein CisA. Elife, 14:-, 2025 Cited by PubMed Abstract: Bacterial contractile injection systems (CIS) are phage tail-like macromolecular complexes that mediate cell-cell interactions by injecting effector proteins into target cells. CIS from (CIS) are localized in the cytoplasm. Under stress, they induce cell death and impact the life cycle. It remains unknown, however, whether CIS require accessory proteins to directly interact with the cytoplasmic membrane to function. Here, we characterize the putative membrane adaptor CisA, a conserved factor in CIS gene clusters across species. We show by cryo-electron tomography imaging and in vivo assays that CIS contraction and function depend on CisA. Using single-particle cryo-electron microscopy, we provide an atomic model of the extended CIS apparatus; however, CisA is not part of the complex. Instead, our findings show that CisA is a membrane protein with a cytoplasmic N-terminus predicted to interact with CIS components, thereby providing a possible mechanism for mediating CIS recruitment to the membrane and subsequent firing. Our work shows that CIS function in multicellular bacteria is distinct from type VI secretion systems and extracellular CIS, and possibly evolved due to the role CIS play in regulated cell death. PubMed: 40626860DOI: 10.7554/eLife.104064 PDB entries with the same primary citation |
| Experimental method | ELECTRON MICROSCOPY (3.8 Å) |
Structure validation
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