Phospholipid headgroups govern area per lipid and emergent elastic properties of bilayers.
Phospholipid headgroups govern area per lipid and emergent elastic properties of bilayers.
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磷脂头基控制着每个脂质的面积和双层的弹性特性。
DOI：
10.1016/j.bpj.2022.09.005
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发表时间：
2022
影响因子：
3.4
通讯作者：
Brown,MichaelF
中科院分区：
文献类型：
--
作者：
Molugu,TrivikramR;Thurmond,RobinL;Alam,ToddM;Trouard,TheodoreP;Brown,MichaelF
磷脂双分子层是液晶材料，其在介观尺度上的分子间相互作用在膜物理性质的出现中具有关键作用。在这里，我们研究了磷脂极性头基和酰基链的生物物理功能的膜与固态2H NMR光谱的综合影响。我们比较了具有全氘代酰基链的磷脂酰乙醇胺和磷脂酰胆碱在固态有序相和液态无序相的结构和动力学性质。我们对1，2-二全氘代棕榈酰-sn-甘油基-3-磷酸乙醇胺（DPPE-d62）和1，2-二全氘代棕榈酰-sn-甘油基-3-磷酸胆碱（DPPC-d62）在凝胶相中的光谱线形分析表明，这两种脂质都具有全反旋链结构。更大的链段有序参数（SCD）观察到在现场（液晶）相DPPE-d62比DPPC-d62膜，而它们的混合物具有中间值，无论氘代脂质类型。我们的研究结果表明，SCD档案的酰基链是由甲基化的头基，并在整个系统的平均。通过自旋晶格（R1Z）和四极级弛豫（R1Q）测量进一步研究了酰基链分子动力学的变化。两个酰基全氘代脂质的弛豫行为的顺序参数的函数表现出明显的差异。TheR1Zrates有一个平方律依赖于SCD，这意味着集体介观动力学，具有较高的弯曲刚度DPPE-d62比DPPC-d62脂质。因此，通过头基的甲基化来重塑脂质的平均和动态性质提供了一种控制生物膜中肽和蛋白质的作用的机制。
Phospholipid bilayers are liquid-crystalline materials whose intermolecular interactions at mesoscopic length scales have key roles in the emergence of membrane physical properties. Here we investigated the combined effects of phospholipid polar headgroups and acyl chains on biophysical functions of membranes with solid-state2H NMR spectroscopy. We compared the structural and dynamic properties of phosphatidylethanolamine and phosphatidylcholine with perdeuterated acyl chains in the solid-ordered (so) and liquid-disordered (ld) phases. Our analysis of spectral lineshapes of 1,2-diperdeuteriopalmitoyl-sn-glycero-3-phosphoethanolamine (DPPE-d62) and 1,2-diperdeuteriopalmitoyl-sn-glycero-3-phosphocholine (DPPC-d62) in theso(gel) phase indicated an all-transrotating chain structure for both lipids. Greater segmental order parameters (SCD) were observed in theld(liquid-crystalline) phase for DPPE-d62than for DPPC-d62membranes, while their mixtures had intermediate values irrespective of the deuterated lipid type. Our results suggest the SCD profiles of the acyl chains are governed by methylation of the headgroups and are averaged over the entire system. Variations in the acyl chain molecular dynamics were further investigated by spin-lattice (R1Z) and quadrupolar-order relaxation (R1Q) measurements. The two acyl-perdeuterated lipids showed distinct differences in relaxation behavior as a function of the order parameter. TheR1Zrates had a square-law dependence on SCD, implying collective mesoscopic dynamics, with a higher bending rigidity for DPPE-d62than for DPPC-d62lipids. Remodeling of lipid average and dynamic properties by methylation of the headgroups thus provides a mechanism to control the actions of peptides and proteins in biomembranes.