Clercx A, Vandenbussche G, Curstedt T, Johansson J, Jörnvall H, Ruysschaert J M
Service de Néonatologie, Hôpital des Enfants Reine Fabiola, Université Libre de Bruxelles, Belgium.
Eur J Biochem. 1995 Apr 15;229(2):465-72.
A synthetic non-palmitoylated form of the pulmonary surfactant protein SP-C and three peptides of different lengths corresponding to its N-terminal and middle parts were reconstituted into dipalmitoylglycerophosphocholine/phosphatidylglycerol (7:3, by mass) lipid bilayers. The adsorption properties of each reconstituted system were determined by measurement of the surface pressure after injection of the samples underneath an air/water interface. Attenuated total reflection infrared spectroscopy provided information about the structure and orientation of peptides in lipid bilayers. The hydrophobic C-terminal helix is crucial for the rapid adsorption as shortening of the C-terminal part drastically restricted this activity. The C-terminal amino acid sequence can however be replaced with that of the second transmembrane helix of bacteriorhodopsin without significantly modifying the adsorption properties. The data suggest that the hydrophobic C-terminal part allows the anchorage of SP-C in the lipid bilayer in such a manner that the N-terminal domain adopts an optimal conformation and orientation for the rapid adsorption of phospholipids at the air/water interface, and/or that a membrane-spanning helix as such is needed for this activity.
将肺表面活性蛋白SP-C的一种合成的非棕榈酰化形式以及对应于其N端和中间部分的三种不同长度的肽重构到二棕榈酰甘油磷酸胆碱/磷脂酰甘油（质量比7:3）脂质双层中。通过在空气/水界面下方注入样品后测量表面压力来确定每个重构系统的吸附特性。衰减全反射红外光谱提供了关于脂质双层中肽的结构和取向的信息。疏水性C端螺旋对于快速吸附至关重要，因为C端部分的缩短会极大地限制这种活性。然而，C端氨基酸序列可以被细菌视紫红质的第二个跨膜螺旋的序列取代，而不会显著改变吸附特性。数据表明，疏水性C端部分允许SP-C以这样一种方式锚定在脂质双层中，即N端结构域采用最佳构象和取向，以便在空气/水界面快速吸附磷脂，和/或这种活性需要这样一个跨膜螺旋。
