Inhibition of aggregation of a biomimic peptidolipid Langmuir monolayer by Congo red studied by UV-vis and infrared spectroscopies.
A synthetic peptidolipid consisted of a hydrocarbon chain with a chain length of C18 and a peptide moiety of IIGLM terminated with an amine group, designated as C18IIGLM-NH2, has been employed as a biomimic model compound of amyloid peptide for exploring molecular interaction and orientation with the use of the Langmuir monolayer and Langmuir-Blodgett film techniques. Inspired by a well-known fact that a stain reagent, Congo red (CR), binds well to the amyloid-mimic part (IIGLM), inhibition of molecular aggregation of C18IIGLM-NH2 by interaction with CR was expected, and it has been investigated by use of surface pressure-area isotherm, surface dipole moment-area isotherm, Brewster-angle microscopy, and UV-vis/infrared spectroscopies. It has been revealed that monomeric CR molecules whose long axis is parallel to the Langmuir monolayer surface are penetrating the C18IIGLM-NH2 Langmuir monolayer, which plays a role of inhibition of molecular aggregation via hydrogen bonding.
Department of Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551, Japan. hasegawa@ chem.titech.ac.jp
Takeshi
T
Hasegawa
Yoshiko
Y
Sato
Tetsuo
T
Okada
Masami
M
Shibukawa
Changqing
C
Li
Jhony
J
Orbulescu
Roger M
RM
Leblanc
D000588:Amines / Q000737:chemistry; D040761:Biomimetic Materials / Q000737:chemistry*; D003224:Congo Red / Q000494:pharmacology*; D006860:Hydrogen Bonding; D008051:Lipid Bilayers / Q000737:chemistry; D008055:Lipids / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods; D013499:Surface Properties; D013816:Thermodynamics
D000588:Amines; D008051:Lipid Bilayers; D008055:Lipids; D010455:Peptides; D003224:Congo Red