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Single channel activity of OmpF-like porin from Yersinia pseudotuberculosis

Tatyana I Rokitskaya1, Elena A Kotova1, Gennadiy A Naberezhnykh2

  • 1Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory 1/40, Moscow 119991, Russia.

Biochimica Et Biophysica Acta
|February 9, 2016
PubMed

Insights

Acidic pH significantly reduces YOmpF porin channel function and conductance, inducing subconductance states. This suggests lipid-protein interactions, like curvature stress, influence porin channel behavior at low pH.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Membrane Protein Research

Background:

  • Yersinia pseudotuberculosis OmpF-like porin (YOmpF) is crucial for nutrient transport.
  • Porin channel activity is sensitive to environmental conditions, including pH.
  • Understanding YOmpF's pH-dependent behavior is key to its function.

Purpose of the Study:

  • Investigate the mechanistic insights into YOmpF function.
  • Compare the effects of pH variation on YOmpF's ion channel activity and membrane binding.
  • Elucidate the role of lipid-protein interactions in YOmpF's pH response.

Main Methods:

  • Planar lipid bilayer reconstitution of YOmpF.
  • Single-channel electrophysiology to measure ion conductance.
  • Analysis of YOmpF binding to lipid membranes at varying pH.

Main Results:

  • Acidification reduced YOmpF single-channel conductance and induced subconductance states.
  • Lysophosphatidylcholine addition mimicked subconductance states, highlighting lipid-protein interactions.
  • YOmpF's membrane binding showed modest pH dependence, but channel potency decreased significantly at acidic pH.

Conclusions:

  • Acidic pH impairs YOmpF channel function, similar to E. coli OmpF.
  • Lipid curvature stress, mediated by lipid-protein interactions, is implicated in subconductance state formation.
  • YOmpF's channel-forming ability is highly sensitive to pH, impacting its role in Yersinia pseudotuberculosis.
Keywords:
Bacterial porinIon channelIonic currentLiposomeLysophosphatidylcholineOuter membrane proteinPlanar bilayer lipid membranepH dependence

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