Effects of the lung surfactant proteinýýB construct Mini-B on lipid bilayer order and topography.
Effects of the lung surfactant proteinýýB construct Mini-B on lipid bilayer order and topography.
复制标题
肺表面活性剂蛋白 A 构建体 Mini-B 对脂质双层顺序和形貌的影响。
DOI：
10.1007/s00249-012-0850-4
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
Morrow,Michael
中科院分区：
文献类型：
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作者：
Palleboina,Dharamaraju;Waring,AlanJ;Notter,RobertH;Booth,Valerie;Morrow,Michael
疏水性肺表面活性蛋白SP-B是生存所必需的。呼吸过程中肺容量的循环需要肺泡空气-水界面处的表面活性脂质-蛋白质层。SP-B可以通过促进表面层和表面活性剂材料的双层储层之间的接触和转移来有助于表面活性剂层的维持和更新。然而，只有小的影响SP-B的磷脂取向顺序模型系统已被报道。在这项研究中，SP-B的N-末端（SP-B8-25）和C-末端（SP-B63-78）螺旋，无论是连接为Mini-B还是未连接但以等量存在，都被掺入模型磷脂混合物或牛脂质提取物表面活性剂中囊泡分散体或机械定向双层样品的形式。氘和磷核磁共振（NMR）被用来表征这些肽对磷脂链取向顺序，头基取向，和响应的脂质-肽混合物的机械取向的云母板的影响。只有小的影响链取向顺序或头基取向，无论是囊泡或机械取向的样品，被认为是。然而，在机械约束的样品中，Mini-B及其组分螺旋确实对脂质-肽混合物形成未取向双层群体的倾向有特定的影响，所述未取向双层群体在NMR实验的时间尺度上不与取向部分交换。即使在存在机械约束的情况下，局部双层取向的改变也可能与材料从双层储层转移到平坦的表面活性层有关，该过程可能需要通过形成高度弯曲的突起来促进接触。
The hydrophobic lung surfactant protein, SP-B, is essential for survival. Cycling of lung volume during respiration requires a surface-active lipid–protein layer at the alveolar air–water interface. SP-B may contribute to surfactant layer maintenance and renewal by facilitating contact and transfer between the surface layer and bilayer reservoirs of surfactant material. However, only small effects of SP-B on phospholipid orientational order in model systems have been reported. In this study, N-terminal (SP-B8–25) and C-terminal (SP-B63–78) helices of SP-B, either linked as Mini-B or unlinked but present in equal amounts, were incorporated into either model phospholipid mixtures or into bovine lipid extract surfactant in the form of vesicle dispersions or mechanically oriented bilayer samples. Deuterium and phosphorus nuclear magnetic resonance (NMR) were used to characterize effects of these peptides on phospholipid chain orientational order, headgroup orientation, and the response of lipid–peptide mixtures to mechanical orientation by mica plates. Only small effects on chain orientational order or headgroup orientation, in either vesicle or mechanically oriented samples, were seen. In mechanically constrained samples, however, Mini-B and its component helices did have specific effects on the propensity of lipid–peptide mixtures to form unoriented bilayer populations which do not exchange with the oriented fraction on the timescale of the NMR experiment. Modification of local bilayer orientation, even in the presence of mechanical constraint, may be relevant to the transfer of material from bilayer reservoirs to a flat surface-active layer, a process that likely requires contact facilitated by the formation of highly curved protrusions.