EMD-11744
Focused refined cryo-EM structure of an extracellular contractile injection system in marine bacterium Algoriphagus machipongonensis, the baseplate complex in extended state applied 6-fold symmetry
EMD-11744
Single-particle2.9 Å
![EMD-11744](https://www.ebi.ac.uk/emdb/images/entry/EMD-11744/400_11744.gif)
Map released: 16/02/2022
Last modified: 16/03/2022
Sample Organism:
Algoriphagus machipongonensis
Sample: The focused refined baseplate complex of an extracellular contractile injection system in marine bacterium Algoriphagus machipongonensis, applied 6-fold symmetry.
Deposition Authors: Xu J
,
Ericson C,
Feldmueller M,
Lien YW
,
Pilhofer M
Sample: The focused refined baseplate complex of an extracellular contractile injection system in marine bacterium Algoriphagus machipongonensis, applied 6-fold symmetry.
Deposition Authors: Xu J
![](http://www.ebi.ac.uk/web_guidelines/images/logos/orcid/orcid_16x16.png)
![](http://www.ebi.ac.uk/web_guidelines/images/logos/orcid/orcid_16x16.png)
![](http://www.ebi.ac.uk/web_guidelines/images/logos/orcid/orcid_16x16.png)
Identification and structure of an extracellular contractile injection system from the marine bacterium Algoriphagus machipongonensis.
Xu J
,
Ericson CF
,
Lien YW
,
Rutaganira FUN
,
Eisenstein F
,
Feldmuller M
,
King N,
Pilhofer M
(2022) Nat Microbiol , 7 , 397 - 410
![](http://www.ebi.ac.uk/web_guidelines/images/logos/orcid/orcid_16x16.png)
![](http://www.ebi.ac.uk/web_guidelines/images/logos/orcid/orcid_16x16.png)
![](http://www.ebi.ac.uk/web_guidelines/images/logos/orcid/orcid_16x16.png)
![](http://www.ebi.ac.uk/web_guidelines/images/logos/orcid/orcid_16x16.png)
![](http://www.ebi.ac.uk/web_guidelines/images/logos/orcid/orcid_16x16.png)
![](http://www.ebi.ac.uk/web_guidelines/images/logos/orcid/orcid_16x16.png)
![](http://www.ebi.ac.uk/web_guidelines/images/logos/orcid/orcid_16x16.png)
(2022) Nat Microbiol , 7 , 397 - 410
Abstract:
Contractile injection systems (CISs) are phage tail-like nanomachines, mediating bacterial cell-cell interactions as either type VI secretion systems (T6SSs) or extracellular CISs (eCISs). Bioinformatic studies uncovered a phylogenetic group of hundreds of putative CIS gene clusters that are highly diverse and widespread; however, only four systems have been characterized. Here we studied a putative CIS gene cluster in the marine bacterium Algoriphagus machipongonensis. Using an integrative approach, we show that the system is compatible with an eCIS mode of action. Our cryo-electron microscopy structure revealed several features that differ from those seen in other CISs: a 'cap adaptor' located at the distal end, a 'plug' exposed to the tube lumen, and a 'cage' formed by massive extensions of the baseplate. These elements are conserved in other CISs, and our genetic tools identified that they are required for assembly, cargo loading and function. Furthermore, our atomic model highlights specific evolutionary hotspots and will serve as a framework for understanding and re-engineering CISs.
Contractile injection systems (CISs) are phage tail-like nanomachines, mediating bacterial cell-cell interactions as either type VI secretion systems (T6SSs) or extracellular CISs (eCISs). Bioinformatic studies uncovered a phylogenetic group of hundreds of putative CIS gene clusters that are highly diverse and widespread; however, only four systems have been characterized. Here we studied a putative CIS gene cluster in the marine bacterium Algoriphagus machipongonensis. Using an integrative approach, we show that the system is compatible with an eCIS mode of action. Our cryo-electron microscopy structure revealed several features that differ from those seen in other CISs: a 'cap adaptor' located at the distal end, a 'plug' exposed to the tube lumen, and a 'cage' formed by massive extensions of the baseplate. These elements are conserved in other CISs, and our genetic tools identified that they are required for assembly, cargo loading and function. Furthermore, our atomic model highlights specific evolutionary hotspots and will serve as a framework for understanding and re-engineering CISs.