TITLE:
Spectroscopic Investigations of β-Amyloid Interactions with Propofol and L-Arginine
AUTHORS:
Saqer M. Darwish, Shurook Y. Aiaidah, Imtiaz M. Khalid, Musa M. Abuteir, Lena Qawasmi
KEYWORDS:
FTIR Spectroscopy, Oligomeric Aβ, Alzheimer’s Disease, Amyloid β-Peptide, Antiparallel β-Sheet
JOURNAL NAME:
Open Journal of Biophysics,
Vol.5 No.2,
April
29,
2015
ABSTRACT: Beta
amyloid (Aβ) aggregation has been
characterized to be responsible for several amyloid diseases. Fourier transform
infrared (FTIR) spectroscopy, fluorescence, and atomic force microscopy (AFM)
are used to investigate induced changes in the secondary structure of Aβ upon thermal denaturation and
interaction with propofol and L-arginine. Spectral analysis has revealed an
effective static quenching for the intrinsic fluorescence of Aβ by propofol and l-arginine with
binding constants of 2.81 × 102 M-1 for Aβ-propofol and 0.37 × 102 M-1 for Aβ-L-arginine. Fourier self-deconvolution
(FSD) technique has been used to evaluate the relative intensity changes in the
spectra of the component bands in the amide I and amide II regions at different
ligand’s concentration in the protein complex. The analysis showed a decrease
in the intensities of the parallel beta bands of propofol and L-arginine
interactions with Aβ, accompanied
with an increase in the antiparallel bands for the Aβ-propofol interaction and a decrease for the Aβ-l-arginine interaction. The relative increase in peaks’
intensities at 1694 cm-1 and 1531 cm-1 for the propofol
interaction is linked to the formation of oligomers in the protein.