The crystal structure of the Bacillus anthracis spore surface protein BclA shows remarkable similarity to mammalian proteins.
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.
Réty
Stéphane
S
Laboratoire de Biotechnologies et Pharmacologie Génétique Appliquées, CNRS, Unité Mixte de Recherche 8113, Ecole Normale Supérieure de Cachan, 61 Avenue du Président Wilson, 94235 Cachan, France.
Salamitou
Sylvie
S
Garcia-Verdugo
Ignacio
I
Hulmes
David J S
DJ
Le Hégarat
Françoise
F
Chaby
Richard
R
Lewit-Bentley
Anita
A
D000818:Animals; D001408:Bacillus anthracis / Q000378:metabolism*; D002942:Circular Dichroism; D015922:Complement C1q / Q000737:chemistry; D018360:Crystallography, X-Ray; D004305:Dose-Response Relationship, Drug; D006801:Humans; D008562:Membrane Glycoproteins / Q000737:chemistry*; D008958:Models, Molecular; D011485:Protein Binding; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry; D013499:Surface Properties; D013501:Surface-Active Agents / Q000737:chemistry; D013696:Temperature; D014409:Tumor Necrosis Factor-alpha / Q000737:chemistry; D014466:Ultraviolet Rays
C470593:BclA protein, Bacillus anthracis; D008562:Membrane Glycoproteins; D011994:Recombinant Proteins; D013501:Surface-Active Agents; D014409:Tumor Necrosis Factor-alpha; D015922:Complement C1q