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Publication Abstract from PubMed

Melioidosis, caused by the Gram-negative bacterium Burkholderia pseudomallei, is a potentially fatal infection endemic in South-east Asia and Northern Australia that is poorly contained by antibiotics. Research efforts to identify antigenic components for a melioidosis vaccine have led to the identification of several proteins, including subunits comprising the flagella that mediate bacterial motility, host colonization and virulence. This report focuses on the B. pseudomallei flagellar hook-associated protein FlgKB p , and provides first insight into the 3D structure of FlgK proteins as targets for structure-based antigen engineering. The FlgKB p crystal structure (presented here at 1.8A resolution) reveals a multi-domain fold, comprising two small beta-domains protruding from a large elongated alpha-helical bundle core. Evident structural similarity to flagellin, the flagellar filament subunit protein, suggests that, depending on the bacterial species, flagellar hook-associated proteins are likely to display a conserved elongated alpha-helical bundle scaffold coupled to a variable number of smaller domains. Furthermore, we present immune sera recognition data confirming, in agreement with previous findings, that recovered melioidosis patients produce elevated levels of antibodies against FlgKB p , in comparison with seronegative and seropositive healthy subjects. Moreover, we show that FlgKB p displays cytotoxic effects on cultured murine macrophages, suggesting an important role in bacterial pathogenesis. Finally, computational epitope prediction methods applied to the FlgKB p crystal structure, coupled to in vitro mapping, allowed us to predict three antigenic regions that locate to discrete protein domains. Taken together, our results point to FlgKB p as a candidate for the design and production of epitope-containing subunits/domains as potential vaccine components. This article is protected by copyright. All rights reserved.

From crystal structure to in silico epitope discovery in Burkholderia pseudomallei flagellar hook-associated protein FlgK.,Gourlay LJ, Thomas RJ, Peri C, Conchillo-Sole O, Ferrer-Navarro M, Nithichanon A, Vila J, Daura X, Lertmemongkolchai G, Titball R, Colombo G, Bolognesi M FEBS J. 2015 Feb 3. doi: 10.1111/febs.13223. PMID:25645451^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.