Membrane Stability in the Presence of Methacrylate Esters
Membrane Stability in the Presence of Methacrylate Esters
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DOI：
10.1021/acs.langmuir.9b03759
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发表时间：
2020-08-25
期刊：
影响因子：
3.9
通讯作者：
Bonev, Boyan B.
中科院分区：
文献类型：
--
作者：
Yeh, Vivien;Goode, Alice;Bonev, Boyan B.
聚（甲基丙烯酸甲酯）的生物生产是一个快速增长的全球性产业，其受到单体甲基丙烯酸酯中间体对生产菌株的细胞毒性的限制。在生物发酵过程中保持高的甲基丙烯酸酯浓度，这是经济上可行的技术所要求的，挑战了细菌膜稳定性和细胞活力。在甲基丙烯酸酯存在下研究模型脂质膜的稳定性提供了对甲基丙烯酸酯毒性机制以及膜组装的基本结构基础的独特分子见解。我们调查的结构和稳定性的模型膜中存在的高水平的甲基丙烯酸酯，使用固态核磁共振（NMR）和小角X射线散射（SAXS）。宽线P-31 NMR光谱表明，甲基丙烯酸丁酯（BMA）可以被纳入到脂质双层的浓度高达75摩尔%，而不会显着破坏膜的完整性和脂酰基链的组成可以影响膜的耐受性和能力，以适应BMA。使用高分辨率的C-13魔角自旋（MAS）NMR，我们表明，75摩尔%的BMA的存在下，脂质的主要转变温度降低了超过12度，这表明，BMA插入之间的脂质链，导致解偶联的集体脂质运动，通常占主导地位的链trans-gauche异构化。SAXS实验不支持双层瓣叶的潜在解偶联以适应单独的BMA亚相，该实验表明即使在80%BMA下膜厚度也保持不变。在极性/非极性界面处的X射线散射对比度降低表明BMA定位在脂质分子之间的该区域中。
Bioproduction of poly(methyl methacrylate) is a fast growing global industry that is limited by cellular toxicity of monomeric methacrylate intermediates to the producer strains. Maintaining high methacrylate concentrations during biofermentation, required by economically viable technologies, challenges bacterial membrane stability and cellular viability. Studying the stability of model lipid membranes in the presence of methacrylates offers unique molecular insights into the mechanisms of methacrylate toxicity, as well as into the fundamental structural bases of membrane assembly. We investigate the structure and stability of model membranes in the presence of high levels of methacrylate esters using solid-state nuclear magnetic resonance (NMR) and small-angle X-ray scattering (SAXS). Wide-line P-31 NMR spectroscopy shows that butyl methacrylate (BMA) can be incorporated into the lipid bilayer at concentrations as high as 75 mol % without significantly disrupting membrane integrity and that lipid acyl chain composition can influence membrane tolerance and ability to accommodate BMA. Using high resolution C-13 magic angle spinning (MAS) NMR, we show that the presence of 75 mol % BMA lowers the lipid main transition temperature by over 12 degrees, which suggests that BMA intercalates between the lipid chains, causing uncoupling of collective lipid motions that are typically dominated by chain trans-gauche isomerization. Potential uncoupling of the bilayer leaflets to accommodate a separate BMA subphase was not supported by the SAXS experiments, which showed that membrane thickness remained unchanged even at 80% BMA. Reduced X-ray scattering contrast at the polar/apolar interface suggests BMA localization in that region between the lipid molecules.