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本文通过Langmuir单层膜的表面压力-平均分子面积(π-A)曲线的测定与分析,分别对髓鞘碱性蛋白(MBP)与细胞膜中不同头部基团脂质分子二棕榈酰基磷脂胆碱(DPPC)和二棕榈酰基磷脂酰乙醇胺(DPPE)在空气/液体界面上的相互作用过程进行了系统研究.实验结果表明:(1)当界面上脂质含量一定时,亚相中随着MBP浓度的增大,DPPC、DPPE单层膜的等温线向平均分子面积较大的方向移动;(2)在单层膜表面压力为10 mN/m时,一个MBP分子分别结合140±3个DPPC分子和100±3个DPPE分子,随着表面压力增大,当MBP分子分别与两种磷脂分子相互作用时,MBP插入到磷脂单层界面的个数逐渐减少;(3)随着蛋白质浓度的增加,脂分子形成的单层膜变得较为疏松,且MBP分子易于插入到分子头部较小的DPPE单层膜中;(4)蛋白质的存在使DPPC单层膜的表面压力逐渐减小,且蛋白质浓度越大表面压力降低越多,DPPC被MBP带入到亚相中越多;(5)对于DPPE单层膜,蛋白质通过与DPPE相互作用插入到界面膜中,引起表面压力增大,且蛋白质浓度越高,压力变化量越大.
In this paper, we measured and analyzed the surface pressure-average molecular area (π-A) curve of Langmuir monolayers, respectively, and analyzed the relationship between myelin basic protein (MBP) and different head group lipid molecules such as dipalmitoyl phospholipid (DPPC) and dipalmitoylphosphatidylethanolamine (DPPE) at the air / liquid interface were systematically studied.The experimental results show that: (1) when the lipid content of the interface is constant, MBP concentration increased and the isotherms of DPPC and DPPE monolayer shifted to the larger average molecular area. (2) When the surface pressure of monolayer was 10 mN / m, one MBP molecule combined with 140 ± 3 DPPC molecules and 100 ± 3 DPPE molecules. With the increase of surface pressure, when the MBP molecules interact with the two phospholipid molecules respectively, the number of MBP inserted into the interface of phospholipid monolayers decreases gradually. (3) With the increase of surface pressure, , The monolayers formed by lipid molecules became loose and the MBP molecules were easily inserted into the smaller DPPE monolayers in the head of the molecule. (4) The presence of protein decreased the surface pressure of DPPC monolayers gradually , And the greater the protein concentration, the more the pressure on the surface decreased, and the DPPC was brought into MBP The more phase; (5) for the DPPE monolayer film, membrane proteins by inserting into the interface interacts with DPPE, causing the surface pressure increases, and the higher the protein concentration, the greater the pressure change amount.