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Quantifying the Cytotoxicity of Staphylococcus aureus Against Human Polymorphonuclear Leukocytes
12:27

Quantifying the Cytotoxicity of Staphylococcus aureus Against Human Polymorphonuclear Leukocytes

Published on: January 3, 2020

Assembly of Staphylococcus aureus leukocidin into a pore-forming ring-shaped oligomer on human polymorphonuclear

N Sugawara1, T Tomita, T Sato

  • 1Laboratory of Applied Microbiology, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan.

Bioscience, Biotechnology, and Biochemistry
|June 25, 1999
PubMed

Insights

Staphylococcal leukocidin, composed of LukS and LukF proteins, forms a ring-shaped pore approximately 2 nm in diameter. This pore facilitates potassium ion efflux and cell swelling, leading to lysis in target cells.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Biochemistry

Background:

  • Staphylococcal leukocidin is a bipartite toxin composed of LukS and LukF proteins.
  • Leukocidin is known to lyse human and rabbit leukocytes and erythrocytes.

Purpose of the Study:

  • To investigate the pore-forming properties of staphylococcal leukocidin.
  • To elucidate the molecular architecture of the leukocidin pore.

Main Methods:

  • Potassium ion efflux assays using rabbit erythrocytes.
  • Electron microscopy of toxin-treated cells.
  • Isolation and characterization of ring-shaped structures.

Main Results:

  • Leukocidin induced potassium efflux and cell swelling, but lysis was inhibited by polyethylene glycols > 2.1 nm.
  • Electron microscopy revealed ring-shaped structures (9 nm outer, 3 nm inner diameter) on target cells.
  • Isolated rings contained LukS and LukF in a 1:1 molar ratio, with a molecular size of 205 kDa.

Conclusions:

  • LukS and LukF assemble into a ~200 kDa ring-shaped oligomer on target cell membranes.
  • This oligomer forms a functional membrane pore with an approximate diameter of 2 nm.

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