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Variation of Antigen 43 self-association modulates bacterial compacting within aggregates and biofilms

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posted on 2022-05-10, 01:56 authored by Julieanne VoJulieanne Vo, GCM Ortiz, M Totsika, AW Lo, SJ Hancock, AE Whitten, Lilian HorLilian Hor, KM Peters, V Ageorges, N Caccia, M Desvaux, MA Schembri, Jason PaxmanJason Paxman, Begona HerasBegona Heras
The formation of aggregates and biofilms enhances bacterial colonisation and infection progression by affording protection from antibiotics and host immune factors. Despite these advantages there is a trade-off, whereby bacterial dissemination is reduced. As such, biofilm development needs to be controlled to suit adaptation to different environments. Here we investigate members from one of largest groups of bacterial adhesins, the autotransporters, for their critical role in the assembly of bacterial aggregates and biofilms. We describe the structural and functional characterisation of autotransporter Ag43 variants from different Escherichia coli pathotypes. We show that specific interactions between amino acids on the contacting interfaces of adjacent Ag43 proteins drives a common mode of trans-association that leads to cell clumping. Furthermore, subtle variation of these interactions alters aggregation kinetics and the degree of compacting within cell clusters. Together, our structure–function investigation reveals an underlying molecular basis for variations in the density of bacterial communities.


This work was supported by the Australian Research Council (ARC) project grants (DP150102287, DP180102987, DP210100673), Future Fellowship (FT130100580), a Discovery Early Career Researcher Award (DE130101169), a National Health and Medical Research Council (NHMRC) Project Grant (GNT1143638) and an NHMRC Fellowship (GNT1106930). Support from INRAE (Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement) and Region Auvergne with FRI IRP (Fond Regional Innovation Institut de Recherche Pharmabiotique) CoMBa grant (AV0003483 and DOS0019690/00) are also acknowledged. We acknowledge the use of the MX1, MX2 and SAXS/WAXS beamlines at the Australian Synchrotron (ANSTO) and the CSIRO Collaborative Crystallisation Centre (; Melbourne, Australia).


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npj Biofilms and Microbiomes





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Springer Nature



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