Study of Molecular Aggregation of Artificial Amyloid in a Langmuir Monolayer by Infrared Spectroscopy
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- 作者：Takeshi Hasegawa ; Yoshiko Sato ; Hiroyuki Kakuda ; Changqing Li ; Jhony Orbulescu ; Roger M. Leblanc
- 刊名：Journal of Physical Chemistry B
- 出版年：2008
- 出版时间：February 7, 2008
- 年：2008
- 卷：112
- 期：5
- 页码：1391 - 1396
- 全文大小：359K
- 年卷期：v.112,no.5(February 7, 2008)
- ISSN：1520-5207
文摘
A synthesized peptidolipid (C18IIGLM-NH2) comprised of a single C18-saturated hydrocarbon chain connectedto the amino acid sequence IIGLM terminated with the NH2 group was spread on water, which formed astable Langmuir monolayer. The Langmuir and Langmuir-Blodgett (LB) films have been characterized bymeasurements of surface pressure-area (
-A) and surface potential-area (
V-A) isotherms and infraredmultiple-angle incidence resolution spectrometry (MAIRS). The Langmuir monolayer had a significantly largerlimiting molecular area than that of a similar molecule of C18IIGLM-OH, which was reported in our previousstudy. The surface dipole moment analysis coupled with the -A isotherm suggested that the C18IIGLM-NH2 monolayer was extraordinarily stiff and the fundamental structure of the monolayer was brought aboutbefore the monolayer compression. The infrared MAIRS analysis of the C18IIGLM-NH2 LB film revealedthat the backbone structure of the monolayer was the 'antiparallel' 
sheet aligned parallel to the substrate.Since the C18IIGLM-OH LB film was made of 'parallel' sheet with a random orientation, it has beenfound that the present C18IIGLM-NH2 Langmuir monolayer has a largely different monolayer structure,although the chemical structures are slightly different from each other by the terminal group only.
-A) and surface potential-area (V-A) isotherms and infraredmultiple-angle incidence resolution spectrometry (MAIRS). The Langmuir monolayer had a significantly largerlimiting molecular area than that of a similar molecule of C18IIGLM-OH, which was reported in our previousstudy. The surface dipole moment analysis coupled with the -A isotherm suggested that the C18IIGLM-NH2 monolayer was extraordinarily stiff and the fundamental structure of the monolayer was brought aboutbefore the monolayer compression. The infrared MAIRS analysis of the C18IIGLM-NH2 LB film revealedthat the backbone structure of the monolayer was the 'antiparallel' sheet aligned parallel to the substrate.Since the C18IIGLM-OH LB film was made of 'parallel' sheet with a random orientation, it has beenfound that the present C18IIGLM-NH2 Langmuir monolayer has a largely different monolayer structure,although the chemical structures are slightly different from each other by the terminal group only.