Secondary structure in lung surfactant SP-B peptides: IR and CD studies of bulk and monolayer phases.
Secondary structure in lung surfactant SP-B peptides: IR and CD studies of bulk and monolayer phases.
复制标题
肺表面活性剂 SP-B 肽的二级结构：本体相和单层相的 IR 和 CD 研究。
DOI：
10.1016/s0005-2736(00)00387-4
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发表时间：
2001
期刊：
影响因子：
--
通讯作者：
Flach,CR
中科院分区：
文献类型：
--
作者：
Dieudonné,D;Mendelsohn,R;Farid,RS;Flach,CR
已知肺表面活性蛋白SP-B促进表面活性剂组分在空气/水界面上的吸附和扩散。这种特性对于肺泡亚相和空气/肺泡表面的体内功能似乎至关重要。合成了3个基于SP-B的氨基酸序列（SP-B1-20，SP-B 9 - 36 A，SP-B40- 60 A），用于研究体相和单分子膜环境中蛋白质-脂质相互作用和结构-功能关系。IR和CD研究报告沿着与传统的表面压力-分子面积（π-A）等温线和IR反射-吸收光谱（IRRAS）的调查进行的空气/水界面。在体相中，螺旋促进环境（甲醇和脂质囊泡的水分散液），SP-B1- 20和SP-B 9 - 36 A含有大量的α-螺旋结构，而在水溶液和单层中观察到不同程度的α-螺旋、无规卷曲和β-折叠。对于SP-B 9 - 36 A观察到最显著的行为，其显示可逆的表面压力诱导的β-折叠形成。体相脂质熔化曲线和单层实验与肽-脂质混合物的体相相互作用的程度和肽表面活性的实质性差异表现出微妙的差异。IRRAS的独特性被强调为肺表面活性肽模拟物的体相和单层环境中评估二级结构的重要性。
Pulmonary surfactant protein SP-B is known to facilitate adsorption and spreading of surfactant components across the air/water interface. This property appears essential for in vivo function in the alveolar subphase and at the air/alveolar surface. Three peptides with amino acid sequences based on SP-B containing predicted α-helical regions (SP-B1-20, SP-B9-36A, SP-B40-60A) have been synthesized to probe structure-function relationships and protein-lipid interaction in bulk phase and monolayer environments. IR and CD studies are reported along with traditional surface pressure-molecular area (π-A) isotherms and IR reflection-absorption spectroscopy (IRRAS) investigations conducted at the air/water interface. In bulk phase, helix-promoting environments (methanol and aqueous dispersions of lipid vesicles), SP-B1-20and SP-B9-36Acontained significant amounts of α-helical structure, whereas varying degrees of α-helix, random coil, and β-sheet were observed in aqueous solutions and monolayers. The most striking behavior was observed for SP-B9-36A, which displayed reversible surface pressure-induced β-sheet formation. Bulk phase lipid melting curves and monolayer experiments with peptide-lipid mixtures showed subtle differences in the degree of bulk phase interaction and substantial differences in peptide surface activity. The uniqueness of IRRAS is emphasized as the importance of evaluating secondary structure in both bulk phase and monolayer environments for lung surfactant peptide mimics is demonstrated.