Structural basis of host cell recognition by the pilus adhesin from Streptococcus pneumoniae

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Thierry Izoré1, Carlos Contreras-Martel, Lamya El Mortaji

  • 1Institut de Biologie Structurale Jean-Pierre Ebel, UMR 5075 (CEA, CNRS, UJF), Grenoble, France.

Structure (London, England : 1993)
|February 16, 2010
PubMed

Insights

Streptococcus pneumoniae uses RrgA pili for infection. This study reveals RrgA

Area of Science:

  • Microbiology
  • Structural Biology
  • Biochemistry

Background:

  • Pili are crucial bacterial virulence factors involved in host cell adhesion.
  • Streptococcus pneumoniae employs RrgA for infection establishment, but its precise functions are not fully understood.

Purpose of the Study:

  • To elucidate the structural basis of RrgA function in Streptococcus pneumoniae.
  • To investigate the role of RrgA's unique structural features in bacterial adhesion and host interaction.

Main Methods:

  • High-resolution crystal structure determination of RrgA.
  • Site-specific mutagenesis to probe domain interactions and stability.
  • Mass spectrometry and thermal shift assays to analyze protein structure and stability.

Main Results:

  • The crystal structure of RrgA reveals a four-domain architecture with eukaryotic and prokaryotic origins.
  • RrgA possesses an integrin I-like domain with inserted arms forming a charged cradle.
  • Intradomain isopeptide bonds are critical for stabilizing the stalk domains of RrgA.

Conclusions:

  • The detailed structure of RrgA provides insights into its mechanism of host cell recognition and adhesion.
  • Stabilizing isopeptide bonds are essential for RrgA's structural integrity and function.
  • RrgA and its homologs may share conserved strategies for extracellular matrix recognition and immune evasion in Gram-positive bacteria.

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