Structure of the AlgKX modification and secretion complex required for alginate production and biofilm attachment in Pseudomonas aeruginosa

Nature Communications, vol. 13, pp. 7631

Abstract

Synthase-dependent secretion systems are a conserved mechanism for producing exopolysaccharides in Gram-negative bacteria. Although widely studied, it is not well understood how these systems are organized to coordinate polymer biosynthesis, modification, and export across both membranes and the peptidoglycan. To investigate how synthase-dependent secretion systems produce polymer at a molecular level, we determined the crystal structure of the AlgK-AlgX (AlgKX) complex involved in Pseudomonas aeruginosa alginate exopolysaccharide acetylation and export. We demonstrate that AlgKX directly binds alginate oligosaccharides and that formation of the complex is vital for polymer production and biofilm attachment. Finally, we propose a structural model for the AlgEKX outer membrane modification and secretion complex. Together, our study provides insight into how alginate biosynthesis proteins coordinate production of a key exopolysaccharide involved in establishing persistent Pseudomonas lung infections.

Authors 12

1. Andreea A. Gheorghita

   University of Toronto · Hospital for Sick Children

   Affiliation as printed

   Department of Biochemistry, University of Toronto, Toronto, ON, Canada

   Program in Molecular Medicine, The Hospital for Sick Children, Toronto, ON, Canada

2. Yancheng E. Li

   California Institute of Technology · University of Toronto · Hospital for Sick Children

   Affiliation as printed

   Department of Biochemistry, University of Toronto, Toronto, ON, Canada

   Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA

   Program in Molecular Medicine, The Hospital for Sick Children, Toronto, ON, Canada

3. Elena N. Kitova

   University of Alberta

   Affiliation as printed

   Department of Chemistry, University of Alberta, Edmonton, AB, Canada

4. Duong T. Bui

   University of Alberta

   Affiliation as printed

   Department of Chemistry, University of Alberta, Edmonton, AB, Canada

5. Roland Pfoh

   Hospital for Sick Children

   Affiliation as printed

   Program in Molecular Medicine, The Hospital for Sick Children, Toronto, ON, Canada

6. Kristin E. Low

   Agriculture and Agri-Food Canada · Hospital for Sick Children · Lethbridge Research and Development Centre

   Affiliation as printed

   Lethbridge Research and Development Centre, Agriculture and Agri-Food Canada, Lethbridge, AB, Canada

   Program in Molecular Medicine, The Hospital for Sick Children, Toronto, ON, Canada

7. Gregory B. Whitfield

   University of Toronto · Hospital for Sick Children · Université de Montréal

   Affiliation as printed

   Department of Biochemistry, University of Toronto, Toronto, ON, Canada

   Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, QC, Canada

   Program in Molecular Medicine, The Hospital for Sick Children, Toronto, ON, Canada

8. Marthe T. C. Walvoort Aachen

   Leiden University · University of Groningen

   Affiliation as printed

   Department of Chemical Biology, Stratingh Institute for Chemistry, University of Groningen, Groningen, The Netherlands

   Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands

9. Qingju Zhang Aachen

   Leiden University · Jiangxi Normal University

   Affiliation as printed

   Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands

   National Research Centre for Carbohydrate Synthesis, Jiangxi Normal University, Nanchang, China

10. Jeroen D. C. Codée Aachen

    Leiden University

    Affiliation as printed

    Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands

11. John S. Klassen

    University of Alberta

    Affiliation as printed

    Department of Chemistry, University of Alberta, Edmonton, AB, Canada

12. P. Lynne Howell corresponding

    University of Toronto · Hospital for Sick Children

    Affiliation as printed

    Department of Biochemistry, University of Toronto, Toronto, ON, Canada. howell@sickkids.ca

    Program in Molecular Medicine, The Hospital for Sick Children, Toronto, ON, Canada. howell@sickkids.ca

    Department of Biochemistry, University of Toronto, Toronto, ON, Canada