EDTA-induced Membrane Fluidization and Destabilization: Biophysical Studies on Artificial Lipid Membranes

• 来源期刊: 生物化学与生物物理学报(英文版)
• 关键词: ethylenediaminetetraacetic acid film balance atomic force microscopy quartz crystal microbalance membrane fluidization and destabilization
• 年，卷（期）: 2007,（11）
• 页码范围: 901-913
• 页数: 13页
• 语种: 英文

摘要

The molecular mechanism of ethylenediaminetetraacetic acid (EDTA)-induced membrane destabilization has been studied using a combination of four biophysical techniques on artificial lipid membranes.Data from Langmuir film balance and epifluorescence microscopy revealed the fluidization and expansion effect of EDTA on phase behavior of monolayers of either 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) or mixtures of DPPC and metal-chelating lipids, such as Nα,Nα-Bis[carboxymethyl]-Nε-[(dioctadecylamino)succinyl]-L-lysine or 1,2-dioleoyl-sn-glycero-3-[N-(5-amino- 1-carboxypentyl iminodiacetic acid) succinyl]. A plausible explanation could be drawn from the electrostatic interaction between negatively charged groups of EDTA and the positively charged choline head group of DPPC.Intercalation of EDTA into the lipid membrane induced membrane curvature as elucidated by atomic force microscopy. Growth in size and shape of the membrane protrusion was found to be time-dependent upon exposure to EDTA. Further loss of material from the lipid membrane surface was monitored in real time using a quartz crystal microbalance. This indicates membrane restabilization by exclusion of the protrusions from the surface. Loss of lipid components facilitates membrane instability, leading to membrane permeabilization and lysis.