Synthesis and Spectroscopic Analysis of Chromophoric Lipids Inducing pH-Dependent Liposome Fusion

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• 作者：Takenori Tomohiro ; ; Yoshikatsu Ogawa ; Hiroaki Okuno ; and Masato Kodaka
• 刊名：Journal of the American Chemical Society
• 出版年：2003
• 出版时间：December 3, 2003
• 年：2003
• 卷：125
• 期：48
• 页码：14733 - 14740
• 全文大小：148K
• 年卷期：v.125,no.48(December 3, 2003)
• ISSN：1520-5126

文摘

We design novel chromophoric amphiphiles 6a-c, which lead to pH-dependent membrane fusionof egg phosphatidylcholine (eggPC) liposome containing them. Lipids 6a-c comprise double alkyl chains,a single chain with a 2-nitrophenol group as a pH trigger, and dipeptide (Asp-Asp) between them. The pKavalues of 2-nitrophenol groups of 6a-c in liposome are larger than that of hydrophilic compound 9 in anaqueous solution. Absorption spectra indicate that the fields around 2-nitrophenol of 6a-c situated inliposome membranes are more hydrophobic than that of 9 in an aqueous solution, whereas the environmentsaround deprotonated 2-nitrophenolate of 6b and 6c are not so hydrophobic as that of 6a. This means thatprotonated 2-nitrophenol groups of 6a-c are embedded in bilayer membranes. Deprotonated 2-nitrophenolgroups of 6b and 6c must be located in less hydrophobic circumstances, while that of 6a is still embeddedin bilayer membranes because of its larger hydrophobicity. Absorption spectra and ¹H NMR spectrarespectively suggest that protonated 2-nitrophenol groups of 6a and those of 6c might take face-to-faceassociations in bilayer membranes.