scholarly journals Conductance Changes in Bovine Serum Albumin Caused by Drug-Binding Triggered Structural Transitions

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1022 ◽  
Author(s):  
Jing Yu ◽  
Yun Chen ◽  
Liqun Xiong ◽  
Xiaoyue Zhang ◽  
Yue Zheng

Proteins, due to their binding selectivity, are promising candidates for fabricating nanoscale bio-sensors. However, the influence of structural change on protein conductance caused by specific protein-ligand interactions and disease-induced degeneration still remains unknown. Here, we excavated the relationship between circular dichroism (CD) spectroscopy and conductive atomic force microscopy (CAFM) to reveal the effect of the protein secondary structures changes on conductance. The secondary structure of bovine serum albumin (BSA) was altered by the binding of drugs, like amoxicillin (Amox), cephalexin (Cefa), and azithromycin (Azit). The CD spectroscopy shows that the α-helical and β-sheet content of BSA, which varied according to the molar ratio between the drug and BSA, changed by up to 6%. The conductance of BSA monolayers in varying drug concentrations was further characterized via CAFM. We found that BSA conductance has a monotonic relation with α-helical content. Moreover, BSA conductance seems to be in connection with the binding ability of drugs and proteins. This work elucidates that protein conductance variations caused by secondary structure transitions are triggered by drug-binding and indicate that electrical methods are of potential application in protein secondary structure analysis.

2021 ◽  
Vol 58 (3) ◽  
pp. 187-194
Author(s):  
Yongbo Song ◽  
Yulan Niu ◽  
Hongyan Zheng ◽  
Ying Yao

Abstract The interactions between cocopropane bis-guanidinium acetates, tallowpropane bis-guanidinium acetates with bovine serum albumin (BSA) in an aqueous solution were studied by fluorescence and circular dichroic spectroscopy measurements. The aim of the study was to elucidate the influence of the hydrophilic group and the length of the hydrophobic chain of these surfactants on the mechanism of binding to BSA. The results revealed that for both surfactants, at low concentrations, the Stern–Volmer plots had an upward curvature and at high concentrations, the quenching efficiency was decreased with increase in surfactant concentration. Different thermodynamics parameters demonstrated the existence of hydrogen bond and van der Waals force which acting as binding forces. Static quenching was observed among the protein and surfactant. The conformation of BSA was changed at higher surfactant concentrations as shown by synchronous fluorescence and CD spectroscopy. This work reveals the mechanism and binding characteristics between guanidine surfactants and protein, and provided the basis for further applications of surfactants.


Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2603
Author(s):  
Andra Mihaela Onaș ◽  
Iuliana Elena Bîru ◽  
Sorina Alexandra Gârea ◽  
Horia Iovu

This study investigates the formation of a graphene oxide-polyamidoamine dendrimer complex (GO-PAMAM) and its association and interaction with bovine serum albumin (BSA). Fourier-transform infrared spectrometry and X-ray photoelectron spectrometry indicated the formation of covalent linkage between the GO surface and PAMAM with 7.22% nitrogen content in the GO-PAMAM sample, and various interactions between BSA and GO-PAMAM, including π-π* interactions at 291.5 eV for the binding energy value. Thermogravimetric analysis highlighted the increasing thermal stability throughout the modification process, from 151 to 192 °C for the 10% weight loss temperature. Raman spectrometry and X-ray diffraction analysis were used in order to examine the complexes’ assembly, showing a prominent (0 0 2) lattice in GO-PAMAM. Dynamic light scattering tests proved the formation of stable graphenic and graphenic-protein aggregates. The secondary structure rearrangement of BSA after interaction with GO-PAMAM was investigated using circular dichroism spectroscopy. We have observed a shift from 10.9% β-sheet composition in native BSA to 64.9% β-sheet composition after the interaction with GO-PAMAM. This interaction promoted the rearrangement of the protein backbone, leading to strongly twisted β-sheet secondary structure architecture.


1974 ◽  
Vol 52 (3) ◽  
pp. 196-202 ◽  
Author(s):  
Lee J. Grota ◽  
Gregory M. Brown

Serotonin, N-acetyl serotonin, and 5-methoxy-N-acetyl serotonin (melatonin) were conjugated to bovine serum albumin (BSA) using formaldehyde. The molar ratio of hapten to protein was determined spectrophotometrically. Spectrophotometric data indicated that serotonin and N-acetyl serotonin but not melatonin were conjugated to bovine serum albumin. Selected hapten–protein conjugates were suspended in Freund's adjuvant and injected into rabbits. Antisera were harvested monthly and screened by double immunodiffusion. Immunodiffusion and inhibition tests indicated that antibodies raised to serotonin–BSA reacted with serotonin and 5-methoxytryptamine but failed to cross react with N-acetyl serotonin or melatonin. Inhibition tests indicated that antibodies to N-acetyl serotonin – BSA reacted with N-acetyl serotonin and cross reacted with melatonin but not with serotonin or 5-methoxytryptamine.


2005 ◽  
Vol 284-286 ◽  
pp. 517-520 ◽  
Author(s):  
Satoshi Nagai ◽  
Kanji Tsuru ◽  
Satoshi Hayakawa ◽  
Akiyoshi Osaka

The structural change of bovine serum albumin (BSA) was analyzed by means of ultraviolet (UV) and circular dichroism (CD) spectroscopy due to in contact with ceramics powders such as Al2O3, SiO2, TiO2, ZrO2, hydroxyapatite and b-tricalcium phosphate. The absorbance of the UV spectra increased for the BSA solution in contact with TiO2, ZrO2 and Al2O3, that is, the BSA solution clouded. This indicated the aggregation of BSA after contact with those ceramics powders. The CD spectroscopy showed that the ordered secondary structure of BSA was diminished on contact with TiO2 and ZrO2. We discussed the protein adsorption property of ceramics on the basis of the magnitude of the interaction forces between proteins and the bioceramics.


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