浓度对髓鞘碱性蛋白与髓磷脂分子间相互作用的影响研究

Effect of Concentration on Monolayer Membrane of Interaction Between Myelin Basic Protein and Myelin Molecule

研究髓鞘碱性蛋白(MBP)与髓鞘脂质间的相互作用机制,有助于阐明髓鞘的结构、功能及其构象,以及与癌症、糖尿病、动脉粥样硬化、多发性硬化症等疾病间的相互关系。利用Langmuir技术研究了空气/Tris-HCl界面上MBP与髓磷脂质分子间的相互作用,分别记录了不同浓度的MBP与POPC、POPE和POPS分子间相互作用的压缩-扩张循环曲线,进而计算了各混合单层膜的表面损失量。实验结果表明,当亚相中MBP浓度增大时,π-Α曲线整体向平均分子面积增大的方向移动。比较发现,MBP的浓度对MBP/POPS混合单层膜构象的影响最大,而对POPE单层膜的影响最小。AFM研究发现,MBP与POPC、POPE和POPS分子发生相互作用后,在界面上形成了大量聚集体,并且混合单层膜的流变性和横向结构也与纯脂质单层膜显著不同。上述研究结果为MBP与不饱和髓磷脂分子POPC、POPE及POPS间的相互作用机制提供了有力的直接证据,有助于从分子水平上理解MBP浓度对髓鞘脂质单层膜构象的影响。

Studying the mechanism of interaction between Myelin Basic Protein(MBP)and different myelin lipids is conducive to understanding the relationship between its structure,function,and conformation and diseases such as cancer,diabetes,atherosclerosis,and multiple sclerosis.In this paper,the Langmuir technique is used to study the interaction of different concentrations of MBP and different types of myelin at the air/Tris-HCl interface.The compression-expansion cycle curves of the interaction of different concentrations of MBP and phospholipids are recorded,and the surface loss of mixed monolayer films is calculated.The experimental results show that when the MBP concentration in the subphase increases,the whole π-Αcurve moves towards the direction of increasing the average molecular area.Comparison reveals that the concentration of MBP has the greatest effect on the MBP/POPS mixed monolayer,followed by POPC,and finally POPE monolayer.In addition,AFM study discloses that the interaction formed many aggregation states,and the rheological properties and lateral structure of the mixed membranes differ greatly from that of pure lipid monolayers.The above results provide more direct and convincing evidence for the interaction of MBP with lipids of different head groups(POPC,POPE and POPS),and help us understand the molecular mechanism that different concentrations of MBP affect the conformation of myelin lipid monolayers.