Differential homotypic and heterotypic interactions of antigen 43 (Ag43) variants in autotransporter-mediated bacterial autoaggregation

Research output: Contribution to journalArticlepeer-review

Authors

  • Valentin Ageorges
  • Marion Schiavone
  • Grégory Jubelin
  • Nelly Caccia
  • Philippe Ruiz
  • Ingrid Chafsey
  • Xavier Bailly
  • Etienne Dague
  • Sabine Leroy
  • Jason Paxman
  • Begoña Heras
  • Frédérique Chaucheyras-Durand
  • Mickaël Desvaux

Colleges, School and Institutes

External organisations

  • Université Clermont Auvergne
  • Lallemand Animal Nutrition
  • Institut National de la Recherche Agronomique, UR346 Epidémiologie Animale, Saint Genès Champanelle, France.
  • LAAS-CNRS
  • La Trobe University
  • Institute for Molecular Biosciences
  • Queensland University of Technology (QUT), Queensland, Australia.
  • The University of Queensland

Abstract

Antigen 43 (Ag43) is a cell-surface exposed protein of Escherichia coli secreted by the Type V, subtype a, secretion system (T5aSS) and belonging to the family of self-associating autotransporters (SAATs). These modular proteins, comprising a cleavable N-terminal signal peptide, a surface-exposed central passenger and an outer membrane C-terminal translocator, self-recognise in a Velcro-like handshake mechanism. A phylogenetic network analysis focusing on the passenger revealed for the first time that they actually distribute into four distinct classes, namely C1, C2, C3 and C4. Structural alignment and modelling analyses demonstrated these classes arose from shuffling of two different subdomains within the Ag43 passengers. Functional analyses revealed that homotypic interactions occur for all Ag43 classes but significant differences in the sedimentation kinetics and aggregation state were present when Ag43C3 was expressed. In contrast, heterotypic interaction occurred in a very limited number of cases. Single cell-force spectroscopy demonstrated the importance of specific as well as nonspecific interactions in mediating Ag43-Ag43 recognition. We propose that structural differences in the subdomains of the Ag43 classes account for different autoaggregation dynamics and propensities to co-interact.

Details

Original languageEnglish
Pages (from-to)11100
JournalScientific Reports
Volume9
Issue number1
Publication statusPublished - 31 Jul 2019