Recognition of aqueous flavin mononucleotide on the surface of binary monolayers of guanidinium and melamine amphiphiles
作者:Katsuhiko Ariga、Ayumi Kamino、Hiroshi Koyano、Toyoki Kunitake
DOI:10.1039/a700081b
日期:——
Recognition of aqueous flavin mononucleotide (FMN) on the surface of
binary monolayers of guanidinium amphiphiles (monoalkyl derivative,
C
18
Gua, or dialkyl derivative, 2C
18
Gua) and the
melamine amphiphile (2C
18
mela-NN) has been investigated by
π–A isotherms, FTIR spectroscopy, and XPS
measurements. π–A Isotherms and FTIR spectra of
C
18
Gua–2C
18
mela-NN (1:1) monolayers show that
there is no direct hydrogen bonding and/or coulombic interactions between
C
18
Gua and 2C
18
mela-NN on pure water and that the
C
18
Gua component is dissolved into the subphase upon
compression. In contrast, the presence of aqueous FMN prevented
C
18
Gua molecules from dissolving into the subphase. Maximum
condensation was observed at a 1:1 ratio in
C
18
Gua–2C
18
mela-NN mixed monolayers on aqueous
FMN. XPS analyses revealed that one FMN molecule was bound to one
C
18
Gua–2C
18
mela-NN (1:1) unit and binding was
saturated at 5×10
-6
mol dm
-3
FMN.
Peak shifts observed in FTIR spectra indicated that the isoalloxiazine
ring in FMN formed hydrogen bonds with 2C
18
mela-NN. These
results support a model that the isoalloxazine and phosphate functions in
FMN are bound via hydrogen bonding to melamine in
2C
18
mela-NN and guanidinium in C
18
Gua, respectively.
Similar binding behaviour of FMN was observed for mixed monolayers of
2C
18
Gua–2C
18
mela-NN.
识别表面的水性黄素单核苷酸(FMN)
胍基两亲物的二元单分子层(单烷基衍生物,
C
18
Gua,或二烷基衍生物,2C
18
卦)和
三聚氰胺两亲物(2C
18
mela-NN)已被研究
π-A 等温线、FTIR 光谱和 XPS
测量。 π–A 等温线和 FTIR 光谱
C
18
卦–2C
18
mela-NN (1:1) 单层表明
之间不存在直接的氢键和/或库仑相互作用
C
18
卦与2C
18
Mela-NN 对纯水的影响
C
18
卦成分溶解到面下相中
压缩。相反,水性 FMN 的存在阻止了
C
18
卦分子溶解成面下相。最大限度
在 1:1 的比例下观察到冷凝
C
18
卦–2C
18
水性上的 mela-NN 混合单层膜
FMN。 XPS 分析表明,一个 FMN 分子与一个
C
18
卦–2C
18
mela-NN (1:1) 单元和结合是
5×10饱和
-6
摩尔摩尔数
-3
FMN。
FTIR 光谱中观察到的峰位移表明异恶嗪
FMN中的环与2C形成氢键
18
梅拉-NN。这些
结果支持异咯嗪和磷酸盐在其中发挥作用的模型
FMN 通过氢键与三聚氰胺结合
2C
18
C 中的 mela-NN 和胍盐
18
分别为卦。
对于混合单层 FMN 观察到类似的结合行为
2C
18
卦–2C
18
梅拉-NN。