Attenuated total reflectance Fourier transform infrared studies of the interaction of melittin, two fragments of melittin, and delta-hemolysin with phosphatidylcholines.
Attenuated total reflectance Fourier transform infrared studies of the interaction of melittin, two fragments of melittin, and delta-hemolysin with phosphatidylcholines.
复制标题
衰减全反射傅立叶变换红外研究蜂毒肽、蜂毒肽的两个片段以及 δ-溶血素与磷脂酰胆碱的相互作用。
DOI：
10.1021/bi00399a020
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发表时间：
1987
期刊：
影响因子：
2.9
通讯作者：
Prendergast,FG
中科院分区：
文献类型：
--
作者：
Brauner,JW;Mendelsohn,R;Prendergast,FG
用衰减全反射傅里叶变换红外光谱(ATR FT-IR)研究了膜裂解肽蜂毒素及其片段1-15(疏水片段)和16-26(亲水性片段)和溶血素诱导1，2-二棕榈酰磷脂酰胆碱和L-棕榈酰磷脂酰胆碱薄层磷脂结构的变化。此外，还确定了多肽的二级结构和螺旋片段相对于双层的取向。蜂毒素在POPC中的插入引起了酰基链的大的顺序扰动和运动速率的增加，如由2850 cm~(-1)附近的对称CH2伸缩振动的频率和半宽度以及该模式的ATR二色性比所监测的。DPPC结构的变化较小，与多肽诱导的酰链静态无序(Guche旋转异构体形成)一致。蜂毒素主要采用非螺旋二级结构，但也有不同比例的β和/或聚集形式。螺旋段优先垂直于双层平面定向。为了半定量地理解观察到的二色性比，我们考虑了蜂毒素/脂类相互作用的几种模式。通过将多肽视为弯曲的刚性杆，建立了其裂解性质的合理模型。DPPC中的亲水片段呈二级结构，螺旋较少。根据其对磷脂酰链组织参数的影响判断，该片段基本上没有穿透双层。DPPC中的疏水片段给出了酰胺I的光谱模式，与主要的/3反平行的褶皱片层和较小的螺旋分数的混合物一致。-溶血素的二级结构以螺旋为主，仅有中等的定向择优。从蜂毒中分离出一种含26个氨基酸的两亲性多肽，被广泛用作研究肽/脂和蛋白质/脂相互作用的模型化合物。该肽在脂类环境中诱导了广泛的效应，包括增加离子通透性，裂解天然和人造膜(Olson等人，1974；Weissmann等人，1969)，以及增强磷脂酶A2的活性(Mollay等人，1976；尤尼斯等人，1977)。蜂毒素在几种环境中的结构，包括晶体形式、水溶液和重组为胶束或脂泡的结构，已经被用过多的物理方法来探索，包括X射线衍射(Terweiger等人，1982)，NMR1光谱(Duourc等人，1976；Lauterwein等人，1980；Brown等人，1982)，圆二色谱(Bello等人，1982)，荧光光谱(Hermetter&Lakowicz，1986；Vogel&Jahnig，1986)，以及振动(IR和拉曼)光谱(Levin等人，1982；Verma等人，1974；Bernard等人，1982)；Dasseux等人，1984；Lavialle等人，1982；Vogel等人，1983；Vogel&Jahnig，1986)。这类研究表明蜂毒素可以以单体或四聚体的形式存在，并且每种形式都可以与脂质相互作用
Attenuated total reflectance Fourier transform infrared spectroscopy (ATR FT-IR) has been used to monitor alterations in phospholipid organization in thin layers of 1, 2-dipalmitoylphosphatidylcholine (DPPC) and l-palmitoyl-2-oleoylphosphatidylcholine (POPC), induced by the membrane lytic peptide melittin, its fragments 1-15 (hydrophobic fragment) and 16—26 (hydrophilic fragment), and-hemolysin. In addition, the secondary structures of the peptides and theorientation of helical fragments were determined with respect to the bilayer. The insertion of melittin into POPC caused large perturbations in the order and increased rates of motion of the acyl chains, as monitored by the frequency and half-widthof the symmetric CH2 stretching vibration near 2850 cm" 1, as well as by the ATR dichroic ratio for this mode. Changes in DPPC organization were less and were consistent with peptide-induced static disordering (gauche rotamer formation) in the acyl chains. Melittin adopted primarily an-helical secondary structure, although varying small proportions of ß and/or aggregated forms were noted. The helical segments were preferentially oriented perpendicular to the bilayer plane. Several modes of melittin/lipid interaction were considered in an attempt to semiquantitatively understand theobserved dichroic ratios. By considering the peptide as a bent rigid rod, a plausible model for its lytic properties has been developed. The hydrophilic fragment in DPPC showed a secondary structurewith little-helix present. As judged by its effect on phospholipid acyl chain organizational parameters, the fragment did not penetrate the bilayer substantially. The hy-drophobic fragment in DPPC gave amide I spectral patterns consistent with a mixture of predominantly/3-antiparallel pleated sheet with a smaller fractionof-helix. Disordering of the lipid acyl chains was induced by this fragment.-Hemolysin exhibited predominantly-helical secondary structure, with only moderate orientational preference. It is suggestedto lie randomly within the bilayer.IN^ elittin, an amphiphilic 26-amino acid peptide isolated from bee venom, has been widely investigated as a model compound for studies of peptide/lipid and protein/lipid interaction. The peptide induces a wide variety of effects in lipidie environments including increase in ionic permeability, lysis of natural and artificial membranes (Olson et al., 1974; Weissmann et al., 1969), and potentiation of phospholipase A2 activity (Mollay et al., 1976; Yunes et al., 1977). The structure of melittinin several environments, including the crystalline form, aqueous solution, and reconstituted into micelles or lipid vesicles, has been probed with a plethora of physical methods including X-ray diffraction (Terwilliger et al., 1982), NMR1 spectroscopy (Dufourc et al., 1976; Lauterwein et al., 1980; Brown et al., 1982), circular dichroism (Bello et al., 1982), fluorescence spectroscopy (Hermetter & Lakowicz, 1986; Vogel & Jahnig, 1986), and vibrational (IR and Raman) spectroscopies (Levin et al., 1982; Verma et al., 1974; Bernard et al., 1982; Dasseux et al., 1984; Lavialle et al., 1982; Vogel et al., 1983; Vogel & Jahnig, 1986). Such studies have shown that melittin can exist in either monomeric or tetrameric forms and that each form may interact with lipid