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Outer Membrane Protein OmpB Methylation May Mediate Bacterial Virulence

David C H Yang1, Amila H Abeykoon2, Bok-Eum Choi1

  • 1Department of Chemistry, Georgetown University, Washington, DC 20057, USA.

Trends in Biochemical Sciences
|October 18, 2017
PubMed

Insights

Bacterial outer membrane protein methylation, particularly lysine methylation in rickettsial OmpB, is linked to virulence. Trimethyllysine clusters in OmpB correlate with high bacterial virulence, offering insights into this post-translational modification.

Area of Science:

  • Microbiology
  • Structural Biology
  • Biochemistry

Background:

  • Methylation of outer membrane proteins (OMPs) is a known factor in bacterial virulence.
  • Lysine methylation in rickettsial OmpB specifically correlates with virulence in Rickettsia species.
  • Similar methylation patterns are observed in other pathogenic bacteria, affecting diseases like typhus and tuberculosis.

Purpose of the Study:

  • To investigate the role of OmpB methylation in rickettsial virulence.
  • To elucidate the structural and biochemical characteristics of methylated OmpB and its methyltransferases.
  • To understand the mechanism of this unusual post-translational modification.

Main Methods:

  • Purification of native rickettsial OmpB from virulent and avirulent strains.
  • Biochemical characterization of OmpB and its methyltransferases.
  • X-ray crystallography to determine the structure of OmpB methyltransferases.

Main Results:

  • Native OmpB from highly virulent Rickettsia strains contains multiple trimethyllysine clusters.
  • Avirulent strains exhibit mostly monomethyllysine with no trimethyllysine.
  • Crystal structures of methyltransferases provided mechanistic insights into catalysis.

Conclusions:

  • The degree of lysine methylation in OmpB, specifically trimethyllysine, is a strong indicator of rickettsial virulence.
  • Structural and biochemical data offer a working model for the mechanism of OmpB methylation.
  • This post-translational modification represents a novel target for understanding and potentially combating bacterial pathogens.
Keywords:
Gram-negative bacteriacrystal structuremethyltransferasesmonomethylationouter membrane proteintrimethylation

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