Fourier-Transform Infrared Spectroscopic Investigation of the Secondary Structure of P2 Protein in Deuterium Oxide Solution

1991 ◽  
Vol 44 (11) ◽  
pp. 1523 ◽  
Author(s):  
BH Stuart ◽  
EF Mcfarlane
Keyword(s):  
Fourier Transform ◽  
Secondary Structure ◽  
Deuterium Oxide ◽  
Resolution Enhancement ◽  
Low Frequency ◽  
Fourier Transform Infrared ◽  
Crystallographic Study ◽  
Fitting Procedures ◽  
P2 Protein ◽  
Α Helix

Fourier transform infrared ( F.t.i.r .) spectroscopy has been used to investigate the secondary structure of bovine P2 protein in deuterium oxide (D2O) solution. The amide 1 region of the spectrum was analysed quantitatively by means of resolution enhancement and band-fitting procedures. The protein was found to consist mainly of β-structure (61%), with a small amount of α-helix (11%). A reason for the existence of an unusually intense low-frequency band assigned to β-structure is discussed. The F.t.i.r . results are compared with those from an X-ray crystallographic study and from circular dichroism and explanations are offered for discrepancies between the results from the different methods.

scholarly journals Structural Changes of β-Casein Induced by Temperature and pH Analysed by Nuclear Magnetic Resonance, Fourier-Transform Infrared Spectroscopy, and Chemometrics

Molecules ◽  
2021 ◽  
Vol 26 (24) ◽  
pp. 7650
Author(s):  
Tatijana Markoska ◽  
Davor Daniloski ◽  
Todor Vasiljevic ◽  
Thom Huppertz
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Fourier Transform ◽  
Magnetic Resonance ◽  
Secondary Structure ◽  
Structural Changes ◽  
Hydrophobic Interactions ◽  
Fourier Transform Infrared ◽  
Helical Structures ◽  
Random Coils ◽  
Α Helix

This study investigated structural changes in β-casein as a function of temperature (4 and 20 °C) and pH (5.9 and 7.0). For this purpose, nuclear magnetic resonance (NMR) and Fourier-transform infrared (FTIR) spectroscopy were used, in conjunction with chemometric analysis. Both temperature and pH had strongly affected the secondary structure of β-casein, with most affected regions involving random coils and α-helical structures. The α-helical structures showed great pH sensitivity by decreasing at 20 °C and diminishing completely at 4 °C when pH was increased from 5.9 to 7.0. The decrease in α-helix was likely related to the greater presence of random coils at pH 7.0, which was not observed at pH 5.9 at either temperature. The changes in secondary structure components were linked to decreased hydrophobic interactions at lower temperature and increasing pH. The most prominent change of the α-helix took place when the pH was adjusted to 7.0 and the temperature set at 4 °C, which confirms the disruption of the hydrogen bonds and weakening of hydrophobic interactions in the system. The findings can assist in establishing the structural behaviour of the β-casein under conditions that apply as important for solubility and production of β-casein.

Secondary Structure Estimation of Proteins Using the Amide III Region of Fourier Transform Infrared Spectroscopy: Application to Analyze Calcium-Binding-Induced Structural Changes in Calsequestrin

1994 ◽  
Vol 48 (11) ◽  
pp. 1432-1441 ◽  
Author(s):  
Fen-Ni Fu ◽  
Daniel B. Deoliveira ◽  
William R. Trumble ◽  
Hemanta K. Sarkar ◽  
Bal Ram Singh
Keyword(s):  
Fourier Transform ◽  
Secondary Structure ◽  
Calcium Binding ◽  
Structural Changes ◽  
Spectroscopic Method ◽  
Spectral Feature ◽  
Protein Secondary Structure ◽  
Fourier Transform Infrared ◽  
Helical Structure ◽  
Α Helix

A Fourier transform infrared spectroscopic method has been developed to analyze protein secondary structure by employing the amide III spectral region (1350–1200 cm−1)· Benefits of using the amide III region have been shown to be substantial. The interference from the water vibration (∼1640 cm−1) in the amide I region can be avoided when one is using the amide III band; furthermore, the amide III region also presents a more characterized spectral feature which provides easily resolved and better defined bands for quantitative analysis. Estimates of secondary structure are accomplished with the use of Fourier self-deconvolution, second derivatization, and curve-fitting on original protein spectra. The secondary structure frequency windows (α-helix, 1328–1289 cm−1; unordered, 1288–1256 cm−1; and β-sheets, 1255–1224 cm−1) have been obtained, and estimates of secondary structural contents are consistent with X-ray crystallography data for model proteins and parallel results obtained with the use of the amide I region. We have further applied the analysis to the structural change of calsequestrin upon Ca2+ binding. Treatment of calsequestrin with 1 mM Ca2+ results in the formation of crystalline aggregates accompanied by a 10% increase in α-helical structure, which is consistent with previous results obtained by Raman spectroscopy. Thus the amide III region of protein IR spectra appears to be a valuable tool in estimating individual protein secondary structural contents.

The effect of aspirin-HSA complexation on the protein secondary structure

2000 ◽  
Vol 78 (2) ◽  
pp. 291-296 ◽  
Author(s):  
J F Neault ◽  
A Novetta-Delen ◽  
H Arakawa ◽  
H Malonga ◽  
H A Tajmir-Riahi
Keyword(s):  
Secondary Structure ◽  
Binding Constant ◽  
Structural Changes ◽  
Resolution Enhancement ◽  
Protein Secondary Structure ◽  
Binding Mode ◽  
Drug Binding ◽  
Drug Concentrations ◽  
Fitting Procedures ◽  
Α Helix

This study was designed to determine the secondary structure of human serum albumin (HSA) in the presence of aspirin in H2O and D2O solutions at physiological pH, using aspirin concentrations of 0.0001-5 mM with final protein concentration of 2% w/v. UV-vis spectra and Fourier transform infrared (FTIR) difference spectroscopy with its self-deconvolution, second derivative resolution enhancement, and curve-fitting procedures were applied to characterize the drug binding mode, the binding constant, and the protein secondary structure in the aspirin-HSA complexes. Spectroscopic evidence showed that no aspirin-protein interaction occurs at very low drug concentration (0.0001 mM), whereas at higher drug contents (0.001-0.1 mM) the aspirin anion binding (H-bonding) is mainly through the ε-amino NH3+ group with overall binding constant of K = 1.4 × 104 M-1. At high drug concentrations (1-5 mM), acetylation of Lys-199 was observed. Aspirin binding results in protein secondary structural changes from that of the α-helix 55% (free HSA) to 49%, β-sheet 22% (free HSA) to 31%, β-anti 12% (free HSA) to 4% and turn 11% (free HSA) to 16% in the aspirin-HSA complexes..Key words: aspirin, protein, drug, binding mode, binding constant secondary structure, FTIR spectroscopy.

Sign in / Sign up

Export Citation Format

Share Document