Baatz J E, Sarin V, Absolom D R, Baxter C, Whitsett J A
University of Cincinnati College of Medicine, Pediatrics/Neonatology Division, OH 45267-0541.
Chem Phys Lipids. 1991 Dec;60(2):163-78. doi: 10.1016/0009-3084(91)90039-e.
The effect of several synthetic peptides based on the sequence of human pulmonary surfactant-associated protein B (SPB) on the molecular packing of model membrane lipids (7:1 dipalmitoyl phosphatidylcholine (DPPC)/dipalmitoyl phosphatidylglycerol (DPPG)) was studied using fluorescence anisotropy. This information was then correlated with complementary biophysical data obtained on both a modified Wilhelmy-Langmuir balance and a pulsating bubble surfactometer. The SP-B peptides examined in these studies are synthetic human SP-B Phe1-Ser78 (SP-B 1-78, full-length sequence), synthetic human SP-B Phe1-Thr60 (SP-B 1-60), synthetic human SP-B Phe1-Ala20 (SP-B 1-20), synthetic human SP-B Ala20-Thr60 (SP-B 20-60), synthetic human SP-B Leu27-Ser78 (SP-B 27-78), synthetic human SP-B Leu40-Thr60 (SP-B 40-60) and synthetic human SP-B Tyr53-Ser78 (SP-B 53-78). trans-parinaric acid was utilized to detect changes in ordering of lipids within the interior upon incorporation of synthetic SP-B peptide, whereas 1-hexadecanoyl-2-[N-(7-nitro-2-benzoxa-1,3-diazol-4-yl)-a min ohexanoyl] phosphatidylcholine (6-NBD-PC) and 1-acyl-2-[N-(7-nitro-2-benzoxa-1,3-diazol-4-yl)aminohexanoyl ] phosphatidylglycerol (6-NBD-PG) were utilized to determine alterations in lipid order at the surface of the model membrane bilayer. With the exception of SP-B 40-60, which corresponds to the most hydrophobic segment of the full-length SP-B, none of the other peptide significantly perturbed the interior bilayer as determined by fluorescence anisotropy of trans-parinaric acid. Incorporation of any of the peptides with the exception of SP-B 40-60, resulted in an increase in anisotropy of NBD-PC. The most significant enhancements resulted from the addition of SP-B 1-78, SP-B 1-20, SP-B 27-78 or SP-B 53-78. The magnitude of anisotropy increase with these peptides is similar to that observed with an equivalent molar ratio of native SP-B isolated from a bovine source. These observations suggest that these four synthetic peptides have the structural and compositional characteristics required for surface ordering of the membrane bilayer in a manner similar to that observed with native SP-B, thereby facilitating the surfactant-like properties of phospholipid mixtures.
利用荧光各向异性研究了几种基于人肺表面活性物质相关蛋白B（SPB）序列的合成肽对模型膜脂（7:1二棕榈酰磷脂酰胆碱（DPPC）/二棕榈酰磷脂酰甘油（DPPG））分子排列的影响。然后将这些信息与在改良的Wilhelmy-Langmuir天平及脉动气泡表面张力仪上获得的补充生物物理数据相关联。在这些研究中检测的SP-B肽包括合成人SP-B Phe1-Ser78（SP-B 1-78，全长序列）、合成人SP-B Phe1-Thr60（SP-B 1-60）、合成人SP-B Phe1-Ala20（SP-B 1-20）、合成人SP-B Ala20-Thr60（SP-B 20-60）、合成人SP-B Leu27-Ser78（SP-B 27-78）、合成人SP-B Leu40-Thr60（SP-B 40-60）和合成人SP-B Tyr53-Ser78（SP-B 53-78）。反式十八碳四烯酸用于检测合成SP-B肽掺入后内部脂质排列的变化，而1-十六烷酰基-2-[N-（7-硝基-2-苯并恶唑-1,3-二唑-4-基）氨基己酰基]磷脂酰胆碱（6-NBD-PC）和1-酰基-2-[N-（7-硝基-2-苯并恶唑-1,3-二唑-4-基）氨基己酰基]磷脂酰甘油（6-NBD-PG）用于确定模型膜双层表面脂质排列的改变。除了对应于全长SP-B最疏水片段的SP-B 40-60外，通过反式十八碳四烯酸的荧光各向异性测定，其他肽均未显著扰动内部双层。除SP-B 40-60外，任何一种肽的掺入都会导致NBD-PC各向异性增加。添加SP-B 1-78、SP-B 1-20、SP-B 27-78或SP-B 53-78导致的各向异性增加最为显著。这些肽导致的各向异性增加幅度与从牛源分离的等量摩尔比天然SP-B观察到的幅度相似。这些观察结果表明，这四种合成肽具有膜双层表面排列所需的结构和组成特征，其方式类似于天然SP-B，从而促进了磷脂混合物的表面活性剂样特性。
