EMD-12032

Single-particle
2.9 Å
EMD-12032 Deposition: 03/12/2020
Map released: 23/02/2022
Last modified: 16/03/2022
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links

EMD-12032

Cryo-EM structure of the contractile injection system crown trimer from Anabaena PCC7120

EMD-12032

Single-particle
2.9 Å
EMD-12032 Deposition: 03/12/2020
Map released: 23/02/2022
Last modified: 16/03/2022
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links
Sample Organism: Nostoc sp. PCC 7120 = FACHB-418
Sample: Base plate complex (C1) of the Anabaena PCC7120 contractile injection system

Deposition Authors: Eisenstein F , Weiss GL , Pilhofer M
Structure of a thylakoid-anchored contractile injection system in multicellular cyanobacteria.
PUBMED: 35165386
DOI: doi:10.1038/s41564-021-01055-y
ISSN: 2058-5276
Abstract:
Contractile injection systems (CISs) mediate cell-cell interactions by phage tail-like structures, using two distinct modes of action: extracellular CISs are released into the medium, while type 6 secretion systems (T6SSs) are attached to the cytoplasmic membrane and function upon cell-cell contact. Here, we characterized a CIS in the multicellular cyanobacterium Anabaena, with features distinct from extracellular CISs and T6SSs. Cryo-electron tomography of focused ion beam-milled cells revealed that CISs were anchored in thylakoid membrane stacks, facing the cell periphery. Single particle cryo-electron microscopy showed that this unique in situ localization was mediated by extensions of tail fibre and baseplate components. On stress, cyanobacteria induced the formation of ghost cells, presenting thylakoid-anchored CISs to the environment. Functional assays suggest that these CISs may mediate ghost cell formation and/or interactions of ghost cells with other organisms. Collectively, these data provide a framework for understanding the evolutionary re-engineering of CISs and potential roles of these CISs in cyanobacterial programmed cell death.