Influence of very-long-chain polyunsaturated fatty acids on membrane structure and dynamics
Influence of very-long-chain polyunsaturated fatty acids on membrane structure and dynamics
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DOI：
10.1016/j.bpj.2022.06.015
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发表时间：
2022-07-19
影响因子：
3.4
通讯作者：
Conboy, John C.
中科院分区：
文献类型：
--
作者：
Cheng, Victoria;Rallabandi, Rameshu;Conboy, John C.
超长链多不饱和脂肪酸（VLC-PUFAs）的独特属性，即它们的长碳链（n - bbb24）和高度不饱和，赋予了这类脂肪酸独特的化学和物理性质。通过VLC-PUFA在1,2-二硬脂酰-sn-3-甘油-磷脂胆碱（dsc）脂质单层中的p-A等温线，评估了VLC-PUFA 32:6 n-3对模型膜脂质堆积和压缩模量的影响。为了比较VLC-PUFA和DSPC脂质单层之间的吸引力或排斥力，将测量的平均分子面积（MMAs）与VLC-PUFA和DSPC理想混合物的计算MMAs进行比较。0.1、1和10 mol %的VLC-PUFA的存在使组成膜的脂质的p-A等温线转向更高的MMAs，并且观察到的与混合VLC-PUFA: dsc单层的理想行为的正偏差对应于VLC-PUFA和dsc之间的排斥力。在0.1、1和10 mol %的VLC-PUFA: dsc混合物中，DSPC的MMA分别为47.1和0.7埃/分子，分别为15,000、1100和91埃/分子，从而估计了VLC-PUFA组分的MMA。VLC-PUFA的大mma表明，二十二碳六烯酸尾部重新插入膜中，并在膜中采用非线性结构，在0.1 mol %的VLC-PUFA中表现得最为明显。与纯DSPC膜相比，0.1 mol % VLC-PUFA: dsc的存在也显著提高了膜的压缩模量28 mN/m。采用和频振动光谱法研究了vllc - pufa对脂质“触发器”的影响。加入0.1 mol %的VLC-PUFA使dsc触发器率提高了四倍。VLC-PUFA促进脂质易位的事实值得注意，因为视网膜膜需要大量的类维生素a流入，这可能是由脂质翻转促进的。
The unique attributes of very-long-chain polyunsaturated fatty acids (VLC-PUFAs), their long carbon chains (n > 24) and high degree of unsaturation, impart unique chemical and physical properties to this class of fatty acids. The changes imparted by VLC-PUFA 32:6 n-3 on lipid packing and the compression moduli of model membranes were evaluated from p-A isotherms of VLC-PUFA in 1,2-distearoyl-sn-3-glycero-phosphocholine (DSPC) lipid monolayers. To compare the attractive or repulsive forces between VLC-PUFA and DSPC lipid monolayers, the measured mean molecular areas (MMAs) were compared with the calculated MMAs of an ideal mixture of VLC-PUFA and DSPC. The presence of 0.1, 1, and 10 mol % VLC-PUFA shifted the p-A isotherm to higher MMAs of the lipids comprising the membrane and the observed positive deviations from ideal behavior of the mixed VLC-PUFA:DSPC monolayers correspond to repulsive forces between VLC-PUFAs and DSPC. The MMA of the VLC-PUFA component was estimated using the measured MMAs of DSPC of 47.1 5 0.7 angstrom(2)/molecule, to be 15,000, 1100, and 91 angstrom(2)/molecule at 0.1, 1, and 10 mol % VLC-PUFA:DSPC mixtures, respectively. The large MMAs of VLC-PUFA suggest that the docosahexaenoic acid tail reinserts into the membrane and adopts a nonlinear structure in the membrane, which is most pronounced at 0.1 mol % VLC-PUFA. The presence of 0.1 mol % VLC-PUFA:DSPC also significantly increased the compression modulus of the membrane by 28 mN/m compared with a pure DSPC membrane. The influence of VLC-PUFA on lipid "flip-flop" was investigated by sum-frequency vibrational spectroscopy. The incorporation of 0.1 mol % VLC-PUFA increased the DSPC flip-flop rate fourfold. The fact that VLC-PUFA promotes lipid translocation is noteworthy as retinal membranes require a high influx of retinoids which may be facilitated by lipid flip-flop.