4.6 Article

Crystal Structure and Self-Interaction of the Type VI Secretion Tail-Tube Protein from Enteroaggregative Escherichia coli

Journal

PLOS ONE
Volume 9, Issue 2, Pages -

Publisher

PUBLIC LIBRARY SCIENCE
DOI: 10.1371/journal.pone.0086918

Keywords

-

Funding

  1. CNRS
  2. AMU
  3. Fondation de la Recherche Medicale [FRM DEQ2011-0421282]
  4. French Infrastructure for Integrated Structural Biology (FRISBI) [ANR-10-INSB-05-01]
  5. Fondation pour la Recherche Medicale [SPF20101221116]
  6. Aix-Marseille Universite
  7. Agence Nationale de la Recherche [ANR-10-JCJC-1303-03]

Ask authors/readers for more resources

The type VI secretion system (T6SS) is a widespread machine used by bacteria to control their environment and kill or disable bacterial species or eukaryotes through toxin injection. The T6SS comprises a central tube formed of stacked hexamers of hemolysin co-regulated proteins (Hcp) and terminated by a trimeric valine-glycine repeat protein G (VgrG) component, the cell puncturing device. A contractile tail sheath, formed by the TssB and TssC proteins, surrounds this tube. This syringe-like machine has been compared to an inverted phage, as both Hcp and VgrG share structural homology with tail components of Caudovirales. Here we solved the crystal structure of a tryptophan-substituted double mutant of Hcp1 from enteroaggregative Escherichia coli and compared it to the structures of other Hcps. Interestingly, we observed that the purified Hcp native protein is unable to form tubes in vitro. To better understand the rationale for observation, we measured the affinity of Hcp1 hexamers with themselves by surface plasmon resonance. The intra-hexamer interaction is weak, with a K-D value of 7.2 mu M. However, by engineering double cysteine mutants at defined positions, tubes of Hcp1 gathering up to 15 stacked hexamers formed in oxidative conditions. These results, together with those available in the literature regarding TssB and TssC, suggest that assembly of the T6SS tube differs significantly from that of Sipho- or Myoviridae.

Authors

I am an author on this paper
Click your name to claim this paper and add it to your profile.

Reviews

Primary Rating

4.6
Not enough ratings

Secondary Ratings

Novelty
-
Significance
-
Scientific rigor
-
Rate this paper

Recommended

No Data Available
No Data Available