BioMetals

, Volume 22, Issue 2, pp 261–274

Hg2+ and Cd2+ interact differently with biomimetic erythrocyte membranes

  • Mary Trang Le
  • Jürgen Gailer
  • Elmar J. Prenner
Article

DOI: 10.1007/s10534-008-9162-7

Cite this article as:
Le, M.T., Gailer, J. & Prenner, E.J. Biometals (2009) 22: 261. doi:10.1007/s10534-008-9162-7

Abstract

In order to characterize the potentially deleterious effects of toxic Hg2+ and Cd2+ on lipid membranes, we have studied their binding to liposomes whose composition mimicked erythrocyte membranes. Fluorescence spectroscopy utilizing the concentration dependent quenching of Phen Green™ SK by Hg2+ and Cd2+ was found to be a sensitive tool to probe these interactions at metal concentrations ≤1 μM. We have systematically developed a metal binding affinity assay to screen for the interactions of Hg2+ or Cd2+ with certain lipid classes. A biomimetic liposome system was developed that contained four major lipid classes of erythrocyte membranes (zwitterionic lipids: phosphatidylcholine and phosphatidylethanolamine; negatively charged: phosphatidylserine and neutral: cholesterol). In contrast to Hg2+, which preferentially bound to the negatively charged phosphatidylserine compared to the zwitterionic components, Cd2+ bound stronger to the two zwitterionic lipids. Thus, the observed distinct differences in the binding affinity of Hg2+ and Cd2+ for certain lipid classes together with their known effects on membrane properties represent an important first step toward a better understanding the role of these interactions in the chronic toxicity of these metals.

Keywords

Toxic metalsHg2+Cd2+LiposomesModel systemsMembranesLipidsErythrocytesFluorescence spectroscopy

Abbreviations

POPC

1-Palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine

POPE

1-Palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine

POPS

1-Palmitoyl-2-oleoyl-sn-glycero-3-[phospho-l-serine]

PC

Phosphatidylcholine

PE

Phosphatidylethanolamine

PS

Phosphatidylserine

Chol

Cholesterol

PGSK

Phen Green™ SK

Copyright information

© Springer Science+Business Media, LLC. 2008

Authors and Affiliations

  • Mary Trang Le
    • 1
  • Jürgen Gailer
    • 2
  • Elmar J. Prenner
    • 1
  1. 1.Department of Biological SciencesUniversity of CalgaryCalgaryCanada
  2. 2.Department of Chemistry and Environmental Science ProgramUniversity of CalgaryCalgaryCanada