pH-Dependent Differential Interacting Mechanisms of Sodium Dodecyl Sulfate with Bovine Serum Fetuin: A Biophysical Insight

Abstract

Sodium dodecyl sulfate (SDS)-glycoprotein interaction serves as a model for a biological membrane. To get mechanistic insight into the interaction of SDS and glycoprotein, the effect of SDS on bovine serum fetuin (BSF) was studied in subcritical micellar concentrations at pH 7.4 and pH 2 using multiple approaches. SDS interacts electrostatically with BSF through its negatively charged head groups at pH 2 and hydrophobically via its alkyl chains at pH 7.4 up to a 1:20 molar ratio of BSF to SDS. However, at higher concentrations of SDS, BSF undergoes amyloid fibril formation at pH 2, as confirmed by enhanced ThT fluorescence, β-sheet formation, and TEM microscopy, whereas BSF undergoes induction of an α-helical structure in the presence of higher SDS concentration at pH 7.4. The increase in α-helical content with increasing SDS concentrations constrains the environment around tryptophan. As a consequence, the interconversion of tryptophan conformers decreases, resulting in a decrement of the fluorescence lifetime for BSF in the presence of SDS at pH 7.4.

Spectroscopic insight into the interaction of bovine serum albumin with imidazolium‐based ionic liquids in aqueous solution

“…We have used the average lifetime (τ avg ) of BSA instead of emphasizing the individual decay constants. The average lifetime values for the biexponential decay were calculated using equation . The lifetime components of BSA in absence and presence of ILs are shown in Table .…”

“…The average lifetime values for the biexponential decay were calculated using equation 4. [68] The lifetime components of BSA in absence and presence of ILs are shown in Table 4. It is observed that the lifetime decreases in the presence of ILs with increasing concentration, which further supports the dynamic quenching of BSA fluorescence by ILs and suggests the existence of a significant interaction between ILs and BSA.…”

“…It is observed that the lifetime decreases in the presence of ILs with increasing concentration, which further supports the dynamic quenching of BSA fluorescence by ILs and suggests the existence of a significant interaction between ILs and BSA. [67,68] Conversely, it is well known that the two common quenchers of tryptophan fluorescence are water molecules and peptide bonds. [69,70] In our case, the quenching by water molecules can be ignored because if the polarity of tryptophan is changed by presence of water molecules, it would make bathochromic shift in fluorescence spectra.…”

A biophysical and computational study unraveling the molecular interaction mechanism of a new Janus kinase inhibitor Tofacitinib with bovine serum albumin

“…Each spectra obtained was the average of 2 scans. The path length of the cells was 0.1 and 1 cm for far‐UV CD (190‐250 nm) and near‐UV CD (250‐300 nm) measurements . The percent of secondary structure was estimated by using online K 2 D software.…”

“…The path length of the cells was 0.1 and 1 cm for far-UV CD (190-250 nm) and near-UV CD (250-300 nm) measurements. 34,35 The percent of secondary structure was estimated by using online K 2 D software. The BSA concentration for far-and near-UV CD measurements was taken as 5μM and 10μM, respectively.…”