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Structural characterization and membrane localization of ExsB from the type III secretion system (T3SS) of

Thierry Izoré1, Caroline Perdu, Viviana Job

  • 1Bacterial Pathogenesis Group, Institut de Biologie Structurale (IBS), Université Grenoble I, France.

Journal of Molecular Biology
|August 16, 2011
PubMed

Insights

Pseudomonas aeruginosa

Area of Science:

  • Microbiology
  • Structural Biology
  • Bacterial Pathogenesis

Background:

  • Pseudomonas aeruginosa utilizes a type III secretion system (T3SS) to deliver toxins into host cells.
  • ExsB, a protein similar to YscW, is found in a T3SS regulatory operon.
  • YscW is a lipoprotein involved in stabilizing the T3SS outer membrane ring.

Purpose of the Study:

  • To investigate the role and structure of ExsB in Pseudomonas aeruginosa's T3SS.
  • To determine the subcellular localization and structural characteristics of ExsB.
  • To compare ExsB's structure with other T3SS lipoproteins.

Main Methods:

  • Expression analysis of ExsB in P. aeruginosa.
  • Subcellular fractionation to determine ExsB localization.
  • High-resolution crystal structure determination of ExsB.
  • Structural comparison with MxiM and Pil lipoproteins.

Main Results:

  • ExsB is expressed and associated with the outer membrane upon T3SS induction.
  • The crystal structure reveals ExsB has a compact β-sandwich fold.
  • ExsB features a basic residue patch potentially involved in membrane recognition.
  • ExsB's structure is distinct from MxiM and Pil lipoproteins.

Conclusions:

  • ExsB is an outer membrane-associated protein involved in the P. aeruginosa T3SS.
  • Structural differences among lipoproteins like ExsB may reflect distinct functional roles in T3SS assembly.
  • This study provides insights into the structural diversity of T3SS components.

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