二次谐波光谱和布鲁斯特角显微镜研究二棕榈酰磷脂酰胆碱和维生素B2的相互作用  

Interaction Between Dipalmityl Phosphatidylcholine and Vitamin B_(2) Studied by Second Harmonic Spectroscopy and Brewster Angle Microscopy

作　　者：刘江清 于长卉 郭源[2,3] 雷圣宾 张贞 LIU Jiang-qing;YU Chang-hui;GUO Yuan;LEI Sheng-bin;ZHANG Zhen(Department of Chemistry,School of Science,Tianjin University,Tianjin 300072,China;Beijing National Research Center for Molecular Sciences,Institute of Chemistry,Chinese Academy of Sciences,Beijing 100190,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]天津大学理学院化学系,天津300072 [2]北京分子科学国家研究中心,中国科学院化学研究所,北京100190 [3]中国科学院大学,北京100049

出　　处：《光谱学与光谱分析》2022年第5期1484-1489,共6页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(21773258,21873104,91856121);北京市自然科学基金项目(2202067)资助。

摘　　要：二棕榈酰磷脂酰胆碱(DPPC)分子在气液界面上形成的Langmuir膜是一种重要的生物膜模拟体系,其手性结构及其与外来物质的相互作用一直是相关学科研究的前沿问题。维生素B_(2)(VB_(2))是人体中一种重要的营养物质,它在代谢障碍引起的脂质沉积性类疾病中有大量的实例应用,经常在一些特殊的临床症状中有出乎意料的治疗奇效。目前,VB_(2)如何参与到膜上生物事件的过程和细胞乃至生命的作用过程中的研究报道较少,特别是VB_(2)分子与磷脂分子靶标的立体相互作用,其可能发生的手性分子识别现象会在许多生物事件中起着关键作用。综合二次谐波-线二色光谱(SHG-LD)、Langmuir膜天平和布鲁斯特角显微镜(BAM)技术初步研究了VB_(2)和DPPC分子在气液界面上的相互作用,分别从气液界面上介观水平和宏观水平上互补表征脂质分子在气液界面上的分子骨架自组装的结构。压缩等温线发现纯水界面L-DPPC和DDPPC液态扩展相/液态凝聚相(LE/LC)共存阶段的膜压几乎不变,race-DPPC的共存相膜压区域稍微缩短,VB_(2)水溶液界面上race-DPPC的LE/LC共存相消失。此外,弹性模量研究表明VB_(2)分子可以提高L-DPPC单分子层膜的弹性模量,但降低D-DPPC和race-DPPC单层膜的弹性模量。结合SHG-LD研究发现,在膜压13mN·m^(-1)下,L-DPPC在纯水和VB_(2)水溶液界面上表面手性过量值(DCE)保持不变。与纯水界面相比较,D-DPPC在VB_(2)水溶液上DCE值出现反转,而race-DPPC的DCE值则不随亚相改变而变化。相同膜压下,BAM观察到单一手性相互作用使得L-DPPC和D-DPPC在纯水界面上各自组装成不同枝臂弯曲方向的手性三叶草微畴(microdomain)。VB_(2)诱导D-DPPC微畴,使其直径增大1~2倍。同时,VB_(2)也诱导了race-DPPC单层膜上近似圆形状的微畴伸展,并长出了三条有曲率的枝臂。对此可以解释为VB_(2)降低了非单一手性相互作用的能量,使得race-DPLangmuir monolayers formed by dipalmityl phosphatidylcholine(DPPC)molecules at the air/liquid interface are an important model system for studying the biomembranes,and their chiral structure and interaction with foreign substances have been the frontiers of related fields.Vitamin B_(2)(VB_(2))is an important medicine for treating lipid deposition diseases caused by metabolic disorders.The molecular mechanism of the interaction between VB_(2) and phospholipids is the key to understanding the function of VB_(2).In this report,the interaction between VB_(2) and DPPC at the air/water interface was studied using second-harmonic generation linear dichroism(SHG-LD),Langmuir membrane balance and Brewster Angle Microscopy(BAM).The compression isotherm shows that the surface pressure in the liquid expansion phase/liquid condensed phase(LE/LC)of L-DPPC and D-DPPC at the water interface is almost unchanged,while the film pressure region in the co-existing phase of race-DPPC is slightly shortened.The LE/LC coexistence phase of race-DPPC disappears at the interface of the VB_(2) aqueous solution.In addition,the elastic modulus studies show that the VB_(2) molecule can increase the elastic modulus of L-DPPC monolayers,but reduce the elastic modulus of D-DPPC and race-DPPC monolayers.SHG-LD results showed that the Degree of Chiral Excess(DCE)of L-DPPC at the interface between VB_(2) and water was unchanged at the surface pressure of 13 mN·m^(-1),and the DCE of D-DPPC at the interface between VB_(2) and water was reversed.The DCE value of race-DPPC does not change with the change of subphase.Under the same surface pressure,BAM observed that the interaction of L-DPPC and D-DPPC to assemble into homochiral microdomains with different arm curvature directions at the pure water interface,and VB_(2) could induced the increase of D-DPPC microdomains by 1 to 2 times.Meanwhile,VB_(2) induced the extension of approximately circular microdomains on race-DPPC monolayer and the growth of three curvature arms,which could be explained as VB_(

关 键 词：二次谐波-线二色谱 布鲁斯特角显微镜 维生素B_(2) 二棕榈酰磷脂酰胆碱 分子间相互作用 手性 

分 类 号：O657.38[理学—分析化学]