Skip to main content

Lund University Publications

LUND UNIVERSITY LIBRARIES

Structure of a novel contractile injection system in Salmonella enterica subsp. salamae

Ejaz, Rooshanie N. ; Funke, Kristin ; Kielkopf, Claudia S. ; Martin, Freddie J.O. ; Šiborová, Marta ; Hendriks, Ivo A. ; Sofos, Nicholas H. ; Pape, Tillmann H. ; Rebrova, Eva Maria LU orcid and Nielsen, Michael L. , et al. (2025)
Abstract
Extracellular contractile injection systems (eCISs) are phage-derived nanomachines used by bacteria to deliver effectors into target cells. Well-studied examples include the Photorhabdus asymbiotica virulence cassettes and the antifeeding prophage from Serratia entomophila, which have been engineered for heterologous cargo delivery. Recent genomic analyses identified previously uncharacterized eCIS gene clusters in the opportunistic human pathogen Salmonella enterica subspecies salamae, but their structure, function, and biotechnological potential remain unexplored. Here, we report a high-resolution cryo-electron microscopy structure of the S. enterica eCIS. Our atomic models reveal a unique sheath architecture, an expansive cage-like... (More)
Extracellular contractile injection systems (eCISs) are phage-derived nanomachines used by bacteria to deliver effectors into target cells. Well-studied examples include the Photorhabdus asymbiotica virulence cassettes and the antifeeding prophage from Serratia entomophila, which have been engineered for heterologous cargo delivery. Recent genomic analyses identified previously uncharacterized eCIS gene clusters in the opportunistic human pathogen Salmonella enterica subspecies salamae, but their structure, function, and biotechnological potential remain unexplored. Here, we report a high-resolution cryo-electron microscopy structure of the S. enterica eCIS. Our atomic models reveal a unique sheath architecture, an expansive cage-like shell around a central spike, and an associated transmembrane hydrolase. We identify a putative effector encoded within the operon exhibiting periplasmic toxicity and provide evidence that the S. enterica eCIS deviates from canonical eCISs by interacting with the inner membrane. Guided by these structural features, we uncover a previously unannotated cluster of contractile injection systems (CISs). Together, our findings expand the known diversity of CIS structures and functions and lay the groundwork for engineering customizable protein delivery platforms. (Less)
Please use this url to cite or link to this publication:
author
; ; ; ; ; ; ; ; and , et al. (More)
; ; ; ; ; ; ; ; ; ; and (Less)
organization
publishing date
type
Working paper/Preprint
publication status
published
subject
publisher
bioRxiv
DOI
10.1101/2025.06.01.657177
language
English
LU publication?
yes
id
f6ca43da-ca0a-44cd-b1e8-477d9ec6468e
date added to LUP
2025-06-03 22:22:26
date last changed
2025-06-04 08:48:25
@misc{f6ca43da-ca0a-44cd-b1e8-477d9ec6468e,
  abstract     = {{Extracellular contractile injection systems (eCISs) are phage-derived nanomachines used by bacteria to deliver effectors into target cells. Well-studied examples include the Photorhabdus asymbiotica virulence cassettes and the antifeeding prophage from Serratia entomophila, which have been engineered for heterologous cargo delivery. Recent genomic analyses identified previously uncharacterized eCIS gene clusters in the opportunistic human pathogen Salmonella enterica subspecies salamae, but their structure, function, and biotechnological potential remain unexplored. Here, we report a high-resolution cryo-electron microscopy structure of the S. enterica eCIS. Our atomic models reveal a unique sheath architecture, an expansive cage-like shell around a central spike, and an associated transmembrane hydrolase. We identify a putative effector encoded within the operon exhibiting periplasmic toxicity and provide evidence that the S. enterica eCIS deviates from canonical eCISs by interacting with the inner membrane. Guided by these structural features, we uncover a previously unannotated cluster of contractile injection systems (CISs). Together, our findings expand the known diversity of CIS structures and functions and lay the groundwork for engineering customizable protein delivery platforms.}},
  author       = {{Ejaz, Rooshanie N. and Funke, Kristin and Kielkopf, Claudia S. and Martin, Freddie J.O. and Šiborová, Marta and Hendriks, Ivo A. and Sofos, Nicholas H. and Pape, Tillmann H. and Rebrova, Eva Maria and Nielsen, Michael L. and Erhardt, Marc and Taylor, Nicholas M. I.}},
  language     = {{eng}},
  month        = {{06}},
  note         = {{Preprint}},
  publisher    = {{bioRxiv}},
  title        = {{Structure of a novel contractile injection system in Salmonella enterica subsp. salamae}},
  url          = {{http://dx.doi.org/10.1101/2025.06.01.657177}},
  doi          = {{10.1101/2025.06.01.657177}},
  year         = {{2025}},
}