Poster Presentation Australian Society for Microbiology Annual Scientific Meeting 2014

Self-associating autotransporter proteins: themes and variations (#258)

Begonia Heras 1 , Jason Paxman 2 , Makrina Totsika 3 , Kate Peters 3 , Mark Schembri 3
  1. LIMS (La Trobe University), Melbourne, VIC, Australia
  2. Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
  3. School of Chemistry and Molecular Biosciences , The University of Queensland, Brisbane, QLD 4072, Australia

Autotransporter (AT) proteins represent a large family of diverse secreted and outer membrane proteins present in numerous Gram-negative bacteria, including all classes of Proteobacteria as well as numerous species of Chlamydiales and Fusobacteria [1-4]. They are a core component of a molecular mechanism for the delivery of cargo protein domains across the outer membrane, and are often associated with important biological functions such as adhesion, aggregation, toxicity and biofilm formation. Furthermore, AT proteins are highly immunogenic and are integral components of human vaccines [5, 6]. Despite their central role in bacterial pathogenesis and potential for vaccine development, the precise molecular mechanism of how AT proteins function is still unknown.

Investigating the structural diversity of AT proteins is essential for understanding their mechanism of action. We have recently elucidated the structure of Antigen 43 (Ag43), an AT protein from uropathogenic E. coli (UPEC) that self associates forming bacterial aggregates and biofilms [7]. Our studies have shown how Ag43's L-shaped structure drives the formation of cell aggregates via a molecular Velcro-like handshake mechanism [8]. Furthermore, our recent studies on other AT proteins from UPEC show unexpected structural diversity among this family of virulence proteins.

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