de Planque Maurits R R, Killian J Antoinette
Department of Biochemistry of Membranes, Center for Biomembranes and Lipid Enzymology, Institute of Biomembranes, Utrecht University, Utrecht, The Netherlands.
Mol Membr Biol. 2003 Oct-Dec;20(4):271-84. doi: 10.1080/09687680310001605352.
Biological membranes are characterized by a heterogeneous composition, which is not only manifested in the wide variety of their components, but also in aspects like the lateral organization, topology, and conformation of proteins and lipids. In bringing about the correct membrane structure, protein-lipid interactions can be expected to play a prominent role. The extent of hydrophobic matching between transmembrane protein segments and lipids potentially constitutes a versatile director of membrane organization, because a tendency to avoid hydrophobic mismatch could result in compensating adaptations such as tilt of the transmembrane segment or segregation into distinct domains. Also, interfacial interactions between lipid headgroups and the aromatic and charged residues that typically flank transmembrane domains may act as an organizing element. In this review, we discuss the numerous model studies that have systematically explored the influence of hydrophobic matching and interfacial anchoring on membrane structure. Designed peptides consisting of a polyleucine or polyleucine/alanine hydrophobic stretch, which is flanked on both sides by tryptophan or lysine residues, reflect the general layout of transmembrane protein segments. It is shown for phosphatidylcholine bilayers and for other model membranes that these peptides adapt a transmembrane topology without extensive peptide or lipid adaptations under conditions of hydrophobic matching, but that significant rearrangements can result from hydrophobic mismatch. Moreover, these effects depend on the nature of the flanking residues, implying a modulation of the mismatch response by interfacial interactions of the flanking residues. The implications of these model studies for the organization of biomembranes are discussed in the context of recent experiments with more complex systems.
生物膜的特点是成分不均一，这不仅体现在其成分种类繁多，还体现在蛋白质和脂质的侧向组织、拓扑结构和构象等方面。在形成正确的膜结构过程中，蛋白质 - 脂质相互作用可能起着重要作用。跨膜蛋白片段与脂质之间疏水匹配的程度可能是膜组织的一个通用导向因素，因为避免疏水不匹配的倾向可能导致补偿性适应，如跨膜片段的倾斜或分离成不同的结构域。此外，脂质头部基团与通常位于跨膜结构域两侧的芳香族和带电荷残基之间的界面相互作用可能作为一种组织元素。在这篇综述中，我们讨论了众多模型研究，这些研究系统地探讨了疏水匹配和界面锚定对膜结构的影响。由聚亮氨酸或聚亮氨酸/丙氨酸疏水片段组成的设计肽，其两侧为色氨酸或赖氨酸残基，反映了跨膜蛋白片段的一般布局。对于磷脂酰胆碱双层膜和其他模型膜的研究表明，在疏水匹配条件下，这些肽能适应跨膜拓扑结构，而无需肽或脂质进行广泛的适应性变化，但疏水不匹配可能导致显著的重排。此外，这些效应取决于侧翼残基的性质，这意味着侧翼残基的界面相互作用会调节不匹配反应。在最近关于更复杂系统的实验背景下，讨论了这些模型研究对生物膜组织的影响。
