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

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.
Journal of Biological Chemistry (Impact Factor: 4.6). 01/2006; 280(52):43073-8. DOI: 10.1074/jbc.M510087200
Source: PubMed

ABSTRACT 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.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Aerosol Science and Technology Publication details, including instructions for authors and subscription information: makes every effort to ensure the accuracy of all the information (the "Content") contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at Bioaerosol detection and identification systems need to be peri-odically checked for assurance that they are responsive to aerosol challenges. Herein, pressurized metered dose inhalers (pMDIs) containing ethanol suspensions of two simulants for B. anthracis spores are considered for providing suitable aerosols. Doses and shot weights from pMDIs with canisters having volumes equal to that of 200 metering-valve actuations were constant for ≤165 actuations, but drop beyond that range. There were statistically significant dose variations between replicate pMDIs and between two types of actuators used on the pMDIs. The storage half-lives of pMDIs filled with Bacillus atrophaeus (BG) and Bacillus thuringiensis subsp. israelensis (Bti) spore formulations are pre-dicted to be 32 and 136 months, respectively, if the canisters are stored under refrigeration (4 • C). The prediction is based on use of a logarithmic regression model relating CFU per actuation to storage time, with data taken at times of 1–12 months. Demon-stration of the utility of the concept was provided by producing responses from a polymerase chain reaction (PCR) identifier with pMDI-generated BG and Bti aerosols that were collected with a 100 L/min wetted wall bioaerosol sampling cyclone.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Bacillus anthracis and other pathogenic Bacillus species form spores that are surrounded by an exosporium, a balloon-like layer that acts as the outer permeability barrier of the spore and contributes to spore survival and virulence. The exosporium consists of a hair-like nap and a paracrystalline basal layer. The filaments of the nap are comprised of trimers of the collagen-like glycoprotein BclA, while the basal layer contains approximately 20 different proteins. One of these proteins, BxpB, forms tight complexes with BclA and is required for attachment of essentially all BclA filaments to the basal layer. Another basal layer protein, ExsB, is required for the stable attachment of the exosporium to the spore. To determine the organization of BclA and BxpB within the exosporium, we used cryo-electron microscopy, cryo-sectioning and crystallographic analysis of negatively stained exosporium fragments to compare wildtype spores and mutant spores lacking BclA, BxpB or ExsB (ΔbclA, ΔbxpB and ΔexsB spores, respectively). The trimeric BclA filaments are attached to basal layer surface protrusions that appear to be trimers of BxpB. The protrusions interact with a crystalline layer of hexagonal subunits formed by other basal layer proteins. Although ΔbxpB spores retain the hexagonal subunits, the basal layer is not organized with crystalline order and lacks basal layer protrusions and most BclA filaments, indicating a central role for BxpB in exosporium organization.
    Journal of Structural Biology 03/2014; 186(1). · 3.37 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A large number of collagen-like proteins have been identified in bacteria during the past ten years, principally from analysis of genome databases. These bacterial collagens share the distinctive Gly-Xaa-Yaa repeating amino acid sequence of animal collagens which underlies their unique triple-helical structure. A number of the bacterial collagens have been expressed in E. coli, and they all adopt a triple-helix conformation. Unlike animal collagens, these bacterial proteins do not contain the post-translationally modified amino acid, hydroxyproline, which is known to stabilize the triple-helix structure and may promote self-assembly. Despite the absence of collagen hydroxylation, the triple-helix structures of the bacterial collagens studied exhibit a high thermal stability of 35 - 39 °C, close to that seen for mammalian collagens. These bacterial collagens are readily produced in large quantities by recombinant methods, either in the original amino acid sequence or in genetically manipulated sequences. This new family of recombinant, easy to modify collagens could provide a novel system for investigating structural and functional motifs in animal collagens and could also form the basis of new biomedical materials with designed structural properties and functions.
    Journal of Structural Biology 01/2014; · 3.37 Impact Factor

Full-text (2 Sources)

Available from
Jun 29, 2014