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.