Article

Preliminary crystallographic analysis of two oligomerization-deficient mutants of the aerolysin toxin, H132D and H132N, in their proteolyzed forms.

Global Health Institute, Ecole Polytechnique Fédérale de Lausanne, Faculty of Life Sciences, Station 15, CH-1015 Lausanne, Switzerland.
Acta Crystallographica Section F Structural Biology and Crystallization Communications (impact factor: 0.51). 12/2010; 66(Pt 12):1626-30. DOI:10.1107/S1744309110041035
Source: PubMed

ABSTRACT Aerolysin is a major virulence factor produced by the Gram-negative bacterium Aeromonas hydrophila and is a member of the β-pore-forming toxin family. Two oligomerization-deficient aerolysin mutants, H132D and H132N, have been overproduced, proteolyzed by trypsin digestion and purified. Crystals were grown from the proteolyzed forms and diffraction data were collected for the two mutants to 2.1 and 2.3 Å resolution, respectively. The prism-shaped crystals belonged to space group C2. The crystal structure of the mutants in the mature, but not heptameric, aerolysin form will provide insight into the intermediate states in the oligomerization process of a pore-forming toxin.

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    Article: Dual chaperone role of the C-terminal propeptide in folding and oligomerization of the pore-forming toxin aerolysin.
    Ioan Iacovache, Matteo T Degiacomi, Lucile Pernot, Sylvia Ho, Marc Schiltz, Matteo Dal Peraro, F Gisou van der Goot
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    ABSTRACT: Throughout evolution, one of the most ancient forms of aggression between cells or organisms has been the production of proteins or peptides affecting the permeability of the target cell membrane. This class of virulence factors includes the largest family of bacterial toxins, the pore-forming toxins (PFTs). PFTs are bistable structures that can exist in a soluble and a transmembrane state. It is unclear what drives biosynthetic folding towards the soluble state, a requirement that is essential to protect the PFT-producing cell. Here we have investigated the folding of aerolysin, produced by the human pathogen Aeromonas hydrophila, and more specifically the role of the C-terminal propeptide (CTP). By combining the predictive power of computational techniques with experimental validation using both structural and functional approaches, we show that the CTP prevents aggregation during biosynthetic folding. We identified specific residues that mediate binding of the CTP to the toxin. We show that the CTP is crucial for the control of the aerolysin activity, since it protects individual subunits from aggregation within the bacterium and later controls assembly of the quaternary pore-forming complex at the surface of the target host cell. The CTP is the first example of a C-terminal chain-linked chaperone with dual function.
    PLoS Pathogens 07/2011; 7(7):e1002135. · 9.13 Impact Factor
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.

Keywords

2.3 Å resolution
 
Gram-negative bacterium Aeromonas hydrophila
 
heptameric
 
intermediate states
 
major virulence factor
 
oligomerization process
 
pore-forming toxin
 
prism-shaped crystals
 
proteolyzed forms
 
space group C2
 
trypsin digestion
 
β-pore-forming toxin family