科研之友
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摘要
The balance of lipid-peptide and peptide- peptide interactions at cell membrane is essential to a large variety of cellular processes. In this study, we have experimentally demonstrated for the first time that sum frequency generation vibrational spectroscopy can be used to probe the peptide-peptide and lipid-peptide interactions in cell membrane in situ and in real time by determination of the line width of amide I band of protein backbone. Using a "benchmark" model of alpha-helical WALP23, it is found that the dominated lipid-peptide interaction causes a narrow line width of the amide I band, whereas the peptide-peptide interaction can markedly broaden the line width. When WALP23 molecules insert into the lipid bilayer, a quite narrow line width of the amide I band is observed because of the lipid- peptide interaction. In contrast, when the peptide lies down on the bilayer surface, the line width of amide I band becomes very broad owing to the peptide-peptide interaction. In terms of the real-time change in the line width, the transition from peptide- peptide interaction to lipid-peptide interaction is monitored during the insertion of WALP23 into 1,2-dipalmitoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (DPPG) lipid bilayer. The dephasing time of a pure alpha-helical WALP23 in 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-(1'-rac-glycerol) and DPPG bilayer is determined to be 2.2 and 0.64 ps, respectively. The peptide-peptide interaction can largely accelerate the dephasing time.
- 出版日期2018-6-26
- 单位中国科学技术大学
