Effect of positively charged short peptides on stability of cubic phases of monoolein/dioleoylphosphatidic acid mixtures
Effect of positively charged short peptides on stability of cubic phases of monoolein/dioleoylphosphatidic acid mixtures
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DOI：
10.1021/la0469607
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发表时间：
2005-06-07
期刊：
影响因子：
3.9
通讯作者：
Yamazaki, M
中科院分区：
文献类型：
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作者：
Masum, SM;Li, SJ;Yamazaki, M
从生物学和物理化学角度阐明具有无限周期最小表面的生物膜立方相的稳定性和相变是必不可少的。在本报告中，我们使用小角 X 射线散射研究了带正电荷的肽-3K (LLKKK) 和聚 (L-赖氨酸) 对含有带负电荷的二油酰磷脂酸 (DOPA) 的单油酸甘油酯 (MO) 膜（即 DOPA/MO 膜）的相稳定性的影响。首先，研究了肽-3K 对处于过量水中的 Q(229) 相的 10% DOPA/90% MO 膜的影响。在 3.4 mM 肽-3K 时，发生 Q(229) 到 Q(230) 相变，在 > 3.4 mM 肽-3K 时，膜处于 Q(230) 相。聚(L-赖氨酸) (M-w 1K-4K) 也诱导 Q(230) 相，但肽-2K (LLKK) 不能在同一膜中诱导它。我们还研究了肽-3K 对 25% DOPA/75% MO 膜的多层囊泡 (MLV) 的影响，该膜处于 L,, 相。在没有肽的情况下，MLV的间距非常大（11.3 nm），但在> = 8 mMpeptide-3K时，无论肽浓度如何，MLV的间距都大大减小到恒定值（5.2 nm），表明peptide-3K和膜形成低含水量的静电稳定聚集体。聚（L-赖氨酸）也大大减小了 25% DOPA/75% MO MLV 的间距，表明形成了类似的聚集体。为了比较肽-3K和聚(L-赖氨酸)与渗透胁迫对立方相稳定性的影响，我们研究了分子量为7500的聚乙二醇(PEG-6K)对10% DOPA/90% MO膜的相稳定性的影响。随着PEG-6K浓度的增加，即随着渗透压的增加，最稳定的相发生如下变化； Q(229)（施瓦茨 P 面）- Q(224) (D) - Q(230) (G)。在此基础上，我们讨论了带正电荷的短肽（peptide-3K）和聚（L-赖氨酸）对DOPA/MO膜的结构和相稳定性的影响机制。
To elucidate the stability and phase transition of cubic phases of biomembranes with infinite periodic minimal surface is indispensable from biological and physicochemical aspects. In this report, we investigated the effect of positively charged peptide-3K (LLKKK) and poly(L-lysine) on the phase stability of monoolein (MO) membranes containing negatively charged dioleoylphosphatidic acid (DOPA) (i.e., DOPA/MO membranes) using small-angle X-ray scattering. At first, the effect of peptide-3K on 10% DOPA/90% MO membrane in excess water, which is in the Q(229) phase, was investigated. At 3.4 mM peptide-3K, a Q(229) to Q(230) phase transition occurred, and at > 3.4 mM peptide-3K, the membrane was in the Q(230) phase. Poly(L-lysine) (M-w 1K-4K) also induced the Q(230) phase, but peptide-2K (LLKK) could not induce it in the same membrane. We also investigated the effect of peptide-3K on the multilamellar vesicle (MLV) of 25% DOPA/75% MO membrane, which is in L,, phase. In the absence of peptide, the spacing of MLV was very large (11.3 nm), but at >= 8 mM peptide-3K, it greatly decreased to a constant value (5.2 nm), irrespective of the peptide concentration, indicating that peptide-3K and the membranes form an electrostatically stabilized aggregation with low water content. Poly(L-lysine) also decreased greatly the spacing of the 25% DOPA/75% MO MLV, indicating the formation of a similar aggregation. To compare the effects of peptide-3K and poly(L-lysine) with that of osmotic stress on stability of the cubic phase, we investigated the effect of poly(ethylene glycol) with molecular weight 7500 (PEG-6K) on the phase stability of 10% DOPA/90% MO membrane. With an increase in PEG-6K concentration, i.e., with an increase in osmotic stress, the most stable phase changed as follows; Q(229) (Schwartz's P surface) - Q(224) (D) - Q(230) (G). On the basis of these results, we discuss the mechanism of the effects of the positively charged short peptides (peptide-3K) and poly(L-lysine) on the structure and phase stability of DOPA/MO membranes.