The N-terminal (1-44) and C-terminal (198-243) peptides of apolipoprotein A-I behave differently at the triolein/water interface.
The N-terminal (1-44) and C-terminal (198-243) peptides of apolipoprotein A-I behave differently at the triolein/water interface.
复制标题
载脂蛋白 A-I 的 N 端 (1-44) 和 C 端 (198-243) 肽在三油酸甘油酯/水界面处表现不同。
DOI：
10.1021/bi7010114
复制
发表时间：
2007
期刊：
影响因子：
2.9
通讯作者：
Small,DonaldM
中科院分区：
文献类型：
--
作者：
Wang,Libo;Hua,Ning;Atkinson,David;Small,DonaldM
Apolipoprotein A-I (apoA-I), the major protein of high-density lipoprotein (HDL), moves between HDL and triacylglycerol-rich lipoproteins during metabolism. We reported that apoA-I is conformationally flexible at the triolein/water (TO/W) interface, partially desorbing at low surface pressure (Π) but totally desorbing at Π > 19 mN/m. We now report the different behavior of the N- and C-terminal peptides of apoA-I ([1−44]apoA-I and [198−243]apoA-I) at the TO/W interface. While both peptides are surface active, [198−243]apoA-I is more stable at the TO/W interface. At equilibrium interfacial tension both peptides desorb from the interface when compressed, but [1−44]apoA-I is pushed off at 13 mN/m while [198−243]apoA-I can withstand Π = 16 mN/m. Neither peptide is very elastic or flexible at the interface. Only at small changes of area (<8%), fast oscillations (4 and 8 s periods), and relatively low concentrations (2 × 10-7M) do these peptides show elastic behavior but with a relatively small modulus compared to that of apoA-I. When mixed together, they appear not to interact on the surface. [1−44]ApoA-I binds more rapidly but is replaced by [198−243]apoA-I within minutes. We suggest that when apoA-I partially desorbs from lipoprotein surfaces during lipid metabolism, the N-terminal is the first to detach while the C-terminal remains on the interface and only desorbs at higher pressures. Thus, the observations that different domains of apoA-I adsorb or desorb with small variations in surface pressure make apoA-I a very flexible protein with multiple functions, one of which is to stabilize surface pressure during lipoprotein metabolism as lipids move in and out of the lipoprotein surface.
