Qiao Lin, Ge Aimin, Liang Yimin, Ye Shen
Catalysis Research Center, Hokkaido University , Sapporo 001-0021, Japan.
J Phys Chem B. 2015 Nov 5;119(44):14188-99. doi: 10.1021/acs.jpcb.5b08985. Epub 2015 Oct 26.
Ambient ozone is a common pollutant in the atmosphere that has an extremely high oxidative ability, can dramatically change the structure and functionality of biomolecules, and is harmful to public health. However, the knowledge about the influence of low-level ozone is still very limited at a molecular level. In the present study, the monolayer of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC, 16:0-18:1 PC) as well as its binary mixed monolayer with 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC, 16:0 PC), which are widely found in many biological systems, have been systematically investigated in a low-level ozone environment (20 ± 10 ppb), by π-A isotherm, sum frequency generation (SFG) vibrational spectroscopy, and atomic force microscopy (AFM). Our results demonstrate that the POPC monolayer is unstable and the C═C moieties in the oleyl chain are selectively oxidized by the low-level ozone. The oxidized lipids from POPC initially remain and reorientate the hydrophilic portion to the water surface and gradually dissolve into the aqueous solution. One should take great caution when using unsaturated lipid molecules to avoid their possible oxidation in the ambient environment. The present study expands and deepens our insights into the oxidation mechanism of unsaturated lipids at a molecular level.
环境臭氧是大气中一种常见污染物，具有极高的氧化能力，能显著改变生物分子的结构和功能，对公众健康有害。然而，在分子水平上，关于低水平臭氧影响的知识仍然非常有限。在本研究中，通过π-A等温线、和频振动光谱（SFG）和原子力显微镜（AFM），在低水平臭氧环境（20±10 ppb）中系统研究了1-棕榈酰-2-油酰-sn-甘油-3-磷酸胆碱（POPC，16:0-18:1 PC）单层及其与1,2-二棕榈酰-sn-甘油-3-磷脂酰胆碱（DPPC，16:0 PC）的二元混合单层，这两种单层在许多生物系统中广泛存在。我们的结果表明，POPC单层不稳定，油酰链中的C═C部分被低水平臭氧选择性氧化。来自POPC的氧化脂质最初会保留下来，并将亲水部分重新定向到水表面，然后逐渐溶解到水溶液中。在使用不饱和脂质分子时应格外小心，以避免它们在环境中可能发生的氧化。本研究在分子水平上拓展并深化了我们对不饱和脂质氧化机制的认识。
