Binding Affinity of Inorganic Mercury and Inorganic Cadmium to Biomimetic Erythrocyte Membranes and their Influence on Membrane Phase Transition
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2013-07-10
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Abstract
Inorganic mercury (Hg2+) and cadmium (Cd2+) are toxic heavy metals linked to the etiology of cancer and diabetes. The binding affinity of these metals to biomimetic erythrocyte (RBC) membranes and their influence on membrane phase transition (Tm) were investigated using isothermal titration calorimetry (ITC) and dynamic light scattering (DLS), respectively. Hg2+ bound plasmalogen phospholipids (PL) 350-2300 times stronger than diacyl lipids. Furthermore, Hg2+ increased the Tm of phosphatidylcholine plasmalogen (PCplas) indicating tighter lipid packing. In contrast, Cd2+ exclusively targeted negatively charged phosphatidylserine (PS) and increased its Tm. Cd2+ presence in metal mixtures (1:1 Hg2+:Cd2+) enhanced Hg binding to diacyl PL’s and significantly increased the Tm of PCplas. Finally, 1 mM Hg2+ and Cd2+ bound rabbit erythrocytes with high affinity and induced echinocyte and RBC vesiculation as visualized by microscopy. The results obtained enhance our understanding of metal-lipid binding and ultimately metal-induced RBC toxicity in mammals.
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Biological Sciences, Toxicology, Biochemistry
Citation
Hassanin, M. (2013). Binding Affinity of Inorganic Mercury and Inorganic Cadmium to Biomimetic Erythrocyte Membranes and their Influence on Membrane Phase Transition (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/25119