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Oms38 is the first identified pore-forming protein in the outer membrane of relapsing fever spirochetes

Marcus Thein1, Ignas Bunikis, Katrin Denker

  • 1Department of Biotechnology, Biocenter, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.

Journal of Bacteriology
|September 2, 2008
PubMed

Insights

Researchers identified Oms38, the first outer membrane-spanning protein (Oms38) in relapsing fever Borrelia species. This protein forms small, anion-selective channels crucial for nutrient uptake during rapid bacterial proliferation.

Area of Science:

  • Microbiology
  • Biochemistry
  • Molecular Biology

Background:

  • Relapsing fever is a global endemic disease caused by Borrelia species.
  • Rapid Borrelia proliferation during fever requires efficient nutrient uptake.
  • Existing research lacks understanding of nutrient transport mechanisms in relapsing fever Borrelia.

Purpose of the Study:

  • To identify and characterize outer membrane proteins involved in nutrient uptake in relapsing fever Borrelia.
  • To investigate the function and properties of a newly identified porin in these pathogens.

Main Methods:

  • Purification of the outer membrane protein using hydroxyapatite chromatography.
  • Biophysical characterization of the purified protein (Oms38) using the black lipid bilayer method.
  • Analysis of deduced amino acid sequences for structural and functional insights.

Main Results:

  • Identification and purification of Oms38, a 38 kDa outer membrane-spanning protein.
  • Oms38 forms small, water-filled channels (80 pS in 1 M KCl) without voltage-dependent closure.
  • The Oms38 channel exhibits slight anion selectivity (cation/anion permeability ratio of 0.41).
  • Sequence analysis revealed an N-terminal signal sequence and high conservation (58% identity) among studied species.

Conclusions:

  • Oms38 is the first characterized porin from relapsing fever Borrelia species.
  • Oms38 likely plays a vital role in facilitating essential nutrient uptake for rapid bacterial growth.
  • The protein's conserved nature suggests a critical function across multiple relapsing fever Borrelia species.

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