拉曼光谱研究乳铁蛋白及其肽段与DPPC、DPPG脂质体的相互作用

Interaction of Lactoferrin and Its Peptides with DPPC and DPPG Liposomes Studied by Raman Spectroscopy

利用拉曼光谱研究了乳铁蛋白及其肽段Lactoferrcin B4-14和Lactoferrampin与DPPC、DPPG脂质体的相互作用。通过分析作用前后两种磷脂拉曼光谱的变化,探讨了乳铁蛋白及其肽段与磷脂的作用模式,为阐明乳铁蛋白及其肽段抗菌机理提供了重要依据。拉曼光谱显示,乳铁蛋白及其肽段加入中性磷脂DPPC脂质体后,属于磷脂脂酰链的C—H对称、反对称伸缩振动的2 847和2 882 cm-1处的峰强没有发生明显改变;而当乳铁蛋白及其肽段与DPPG作用后,2 882 cm-1处的峰强度明显下降,磷脂的侧向相互作用序参数由未加入时的0.19分别下降到了0.17,0.14,0.12,变化率分别为-11%,-27%,-34%,表明乳铁蛋白及其肽段可能通过静电相互作用与负电性DPPG脂质体吸引并结合,且Lactoferrcin B4-14和Lactoferrampin比乳铁蛋白与磷脂的作用更为强烈。

Interaction of lactoferrin and its peptides LfcinB4-14 and LfampinB with dipalmitoylglycero-phosphocholine（DPPC） and dipalmitoylglycero-phosphoglycerol（DPPG） liposomes were studied by means of Raman spectroscopy.In our study,conformational changes in the phospholipid molecules were investigated by measuring the intensities of 2 847 and 2 882 cm-1 Raman bands which are assigned to acyl chains＇ symmetric and asymmetric C—H stretching vibrations.The addition of lactoferrin and its peptides LfcinB4-14 and LfampinB caused a decrease in the 2 882 cm-1 intensity of DPPG liposomes,thus the order parameter for the lateral interactions between chains Slat decreased from 0.19 to 0.17, 0.14 and 0.12 respectively.On the contrary,the intensities at 2 847 and 2 882 cm-1 of DPPC liposomes were poorly affected by lactoferrin and its peptides.The results show that lactoferrin and its peptides present a stronger effect on the molecular structure and order degree of anionic lipid DPPG than that of zwitterionic lipid DPPC.This suggests that lactoferrin,LfcinB4-14 and LfampinB can interact and combine with the negatively charged DPPG liposomes by electrostatic interaction and perform its antibacterial activity.Besides,LfcinB4-14 and LfampinB can affect the lipid more strongly than lactoferrin.