Proteolytically-induced changes of secondary structural protein conformation of bovine serum albumin monitored by Fourier transform infrared (FT-IR) and UV-circular dichroism spectroscopy

Effect of oxidation induced by hydroxyl radical‐mediated model on molecular structural and physical character of egg white powder

“…There was no significant change in random coil in the EWP after oxidation. At low H 2 O 2 concentrations, the β‐turn content decreased and the content of β‐sheet increased, indicating that oxidation might cause aggregation, because the cross‐linking of proteins could form an intermolecular β‐sheet structure(Guler et al .,). However, when the concentration reached 10 and 20 mmol L −1 , the relative content of β‐sheet decreased, it might be due to the cleavage of the peptide chain of the EWP under high concentration, which led to the change in the protein structure as reported that high oxidative conditions lead to breakage of protein peptide chains (Lund et al .,).…”

Effects of freezing and the cryoprotectant lactobionic acid in the structure of GlnK protein evaluated by circular dichroism (CD) and isothermal titration calorimetry (ITC)

“…Different protein sources have specific percentages and ratios of a-helix and b-sheet in their protein secondary structures. Some studies also indicated that these structures can be modified by the protein environment as a solvent, temperature and binder (Whamond and Thornton 2006; Güler et al 2016). The GlnK structure curves obtained in this study present a positive maximum at 195 nm, a negative minimum at 206 nm and shoulder at 217 nm (Fig.…”

“…Nevertheless, these authors suggest that the freeze-thaw cycles caused a change in the molecule structure and a bigger exposure of the hydrophobic side-chain groups. Changes in the protein structures were also studied by Güler et al (2016) in terms of enzymatic breakdown of the bovine serum albumin. Although proteolysis reaction causes more damage to protein structures than freeze-thaw cycles, both processes result in similar changes to CD spectra.…”

“…Although proteolysis reaction causes more damage to protein structures than freeze-thaw cycles, both processes result in similar changes to CD spectra. Güler et al (2016) demonstrated that the decrease of the ellipticity to around 190-195 nm indicated a loss of a-helix structure resulting from the breakdown of the enzyme into smaller fragments. At the same time, increase of the ellipticity values to 222 nm indicates a breakdown of secondary structure elements and therefore the degradation of BSA.…”

Octave-spanning mid-infrared pulses by plasma generation in air pumped with an Yb:KGW source

“…We consider direct IR excitation of a strong chromophore: the amide I vibration of a globular protein, bovine serum albumin [29], in the 1600–1700 cm −1 region (molar absorptivity ∊ ~ 3 × 10 5 M −1 cm −1 or absorption cross section σ ~ 1 × 10 −15 cm 2 ). For a diffraction-limited spot formed using an NA = 0.65 microscope objective (spot area A ~ 6 × 10 −7 cm 2 ), 1 in 6 × 10 8 photons (A/ σ ) would be absorbed.…”