The crystal structure of the Bacillus anthracis spore surface protein BclA shows remarkable similarity to mammalian proteins.

Stéphane Réty (1) , Sylvie Salamitou (2) , Ignacio Garcia-Verdugo (3) , David J S Hulmes (4) , Françoise Le Hégarat (2) , Richard Chaby (3) , Anita Lewit-Bentley (1)

1 LBPA - Laboratoire de Biologie et de Pharmacologie Appliquée
2 IGM - Institut de génétique et microbiologie [Orsay]
3 IBBMC - Institut de biochimie et biophysique moléculaire et cellulaire
4 IBCP - Institut de biologie et chimie des protéines [Lyon]

The lethal disease anthrax is propagated by spores of Bacillus anthracis, which can penetrate into the mammalian host by inhalation, causing a rapid progression of the disease and a mostly fatal outcome. We have solved the three-dimensional structure of the major surface protein BclA on B. anthracis spores. Surprisingly, the structure resembles C1q, the first component of complement, despite there being no sequence homology. Although most assays for C1q-like activity, including binding to C1q receptors, suggest that BclA does not mimic C1q, we show that BclA, as well as C1q, interacts with components of the lung alveolar surfactant layer. Thus, to better recognize and invade its hosts, this pathogenic soil bacterium may have evolved a surface protein whose structure is strikingly close to a mammalian protein.

Domaines: Biologie cellulaire

Stéphane Réty, Sylvie Salamitou, Ignacio Garcia-Verdugo, David J S Hulmes, Françoise Le Hégarat, et al.. The crystal structure of the Bacillus anthracis spore surface protein BclA shows remarkable similarity to mammalian proteins.. Journal of Biological Chemistry, 2005, 280 (52), pp.43073-8. ⟨10.1074/jbc.M510087200⟩. ⟨hal-00287081⟩