HgCl2 disrupts the structure of the human erythrocyte membrane and model phospholipid bilayers

The structural effects of Hg(II) ions on the erythrocyte membrane were stud ied through the interactions of HgCl2 with human erythrocytes and their iso lated resealed membranes. Studies were carried out by scanning electron mic roscopy and fluorescence spectroscopy, respectively. Hg(II) induced shape c hanges in erythrocytes, which took the form of echinocytes and stomatocytes . This finding means that Hg(II) locates in both the outer and inner monola yers of the erythrocyte membrane. Fluorescence spectroscopy results indicat e strong interactions of Hg(II) ions with phospholipid amino groups, which also affected the packing of the lipid acyl chains at the deep hydrophobic core of the membrane. HgCl2 also interacted with bilayers of dimyristoylpho sphatidylcholine and dimyristoylphosphatidylethanolamine, representative of phospholipid classes located in the outer and inner monolayers of the eryt hrocyte membrane, respectively. X-ray diffraction indicated that Hg(II) ion s induced molecular disorder to both phospholipid bilayers, while fluoresce nce spectroscopy of dimyristoylphosphatidylcholine large unilamellar vesicl es confirmed the interaction of Hg(II) ions with the lipid polar head group s. All these findings point to the important role of the phospholipid bilay ers in the interaction of Hg(II) on cell membranes. (C) 2000 Elsevier Scien ce S.A. All rights reserved.