scholarly journals Changes in Glycated Human Serum Albumin Binding Affinity for Losartan in the Presence of Fatty Acids In Vitro Spectroscopic Analysis

Molecules ◽  
2022 ◽  
Vol 27 (2) ◽  
pp. 401
Author(s):  
Agnieszka Szkudlarek ◽  
Jadwiga Pożycka ◽  
Karolina Kulig ◽  
Aleksandra Owczarzy ◽  
Wojciech Rogóż ◽  
...  

Conformational changes in human serum albumin due to numerous modifications that affect its stability and biological activity should be constantly monitored, especially in elderly patients and those suffering from chronic diseases (which include diabetes, obesity, and hypertension). The main goal of this study was to evaluate the effect of a mixture of fatty acids (FA) on the affinity of losartan (LOS, an angiotensin II receptor (AT1) blocker used in hypertension, a first-line treatment with coexisting diabetes) for glycated albumin—simulating the state of diabetes in the body. Individual fatty acid mixtures corresponded to the FA content in the physiological state and in various clinical states proceeding with increased concentrations of saturated (FAS) and unsaturated (FAUS) acids. Based on fluorescence studies, we conclude that LOS interacts with glycated human serum albumin (af)gHSA in the absence and in the presence of fatty acids ((af)gHSAphys, (af)gHSA4S, (af)gHSA8S, (af)gHSA4US, and (af)gHSA8US) and quenches the albumin fluorescence intensity via a static quenching mechanism. LOS not only binds to its specific binding sites in albumins but also non-specifically interacts with the hydrophobic fragments of its surface. Incorrect contents of fatty acids in the body affect the drug pharmacokinetics. A higher concentration of both FAS and FAUS acids in glycated albumin reduces the stability of the complex formed with losartan. The systematic study of FA and albumin interactions using an experimental model mimicking pathological conditions in the body may result in new tools for personalized pharmacotherapy.

2021 ◽  
Vol 89 (3) ◽  
pp. 30
Author(s):  
Anna Ploch-Jankowska ◽  
Danuta Pentak ◽  
Jacek E. Nycz

Human serum albumin (HSA) is the most abundant human plasma protein. HSA plays a crucial role in many binding endos- and exogenous substances, which affects their pharmacological effect. The innovative aspect of the study is not only the interaction of fatted (HSA) and defatted (dHSA) human serum albumin with ibuprofen (IBU), but the analysis of the influence of temperature on the structural modifications of albumin and the interaction between the drug and proteins from the temperature characteristic of near hypothermia (308 K) to the temperature reflecting inflammation in the body (312 K and 314 K). Ibuprofen is a non-steroidal anti-inflammatory drug. IBU is used to relieve acute pain, inflammation, and fever. To determine ibuprofen’s binding site in the tertiary structure of HSA and dHSA, fluorescence spectroscopy was used. On its basis, the fluorescent emissive spectra of albumin (5 × 10−6 mol/dm3) without and with the presence of ibuprofen (1 × 10−5–1 × 10−4 mol/dm3) was recorded. The IBU-HSA complex’s fluorescence was excited by radiation of wavelengths of λex 275 nm and λex 295 nm. Spectrophotometric spectroscopy allowed for recording the absorbance spectra (zero-order and second derivative absorption spectra) of HSA and dHSA under the influence of ibuprofen (1 × 10−4 mol/dm3). To characterize the changes of albumin structure the presence of IBU, circular dichroism was used. The data obtained show that the presence of fatty acids and human serum albumin temperature influences the strength and type of interaction between serum albumin and drug. Ibuprofen binds more strongly to defatted human serum albumin than to albumin in the presence of fatty acids. Additionally, stronger complexes are formed with increasing temperatures. The competitive binding of ibuprofen and fatty acids to albumin may influence the concentration of free drug fraction and thus its therapeutic effect.


2005 ◽  
Vol 387 (3) ◽  
pp. 695-702 ◽  
Author(s):  
Bill X. HUANG ◽  
Chhabil DASS ◽  
Hee-Yong KIM

Mass spectrometry with chemical cross-linking was used to probe the conformational changes of HSA (human serum albumin) in solution on interaction with monounsaturated OA (oleic acid) or polyunsaturated AA (arachidonic acid) or DHA (docosahexaenoic acid). Fatty acid-free or -bound HSA was modified with lysine-specific cross-linkers and digested with trypsin. Cross-linked peptides were analysed by nano-electrospray ionization MS to localize the sites of cross-linking. Our data indicated that a local conformational change involving movement of the side chains of Lys-402 of subdomain IIIA or Lys-541 of subdomain IIIB occurred upon binding of all three fatty acids. Our data also indicated that the side chains of Lys-205 (IIA) and Lys-466 (IIIA) moved closer towards each other upon binding AA or DHA, but not OA, suggesting that the conformations of HSA when bound to mono- and poly-unsaturated fatty acids are distinctively different. While these observations agreed with previous X-ray crystallographic studies, the distances between ε-amino groups of most cross-linked lysine pairs were shorter than the crystal structure predicted, possibly reflecting a discrepancy between the solution and crystal structures. This method can serve as a useful complement to X-ray crystallography, particularly in probing the structure of a protein in solution.


Author(s):  
SYAHPUTRA WIBOWO ◽  
SRI WIDYARTI ◽  
AKHMAD SABARUDIN ◽  
DJOKO WAHONO SOEATMADJI ◽  
SUTIMAN BAMBANG SUMITRO

Objectives: Albumin in diabetes mellitus undergoes conformational changes that affect the ability as an endogenous scavenger. Treatment with astaxanthin (ASX) expected to improve the function of albumin in case of diabetes mellitus. The objectives of this study are to compare the capability of ASX and metformin to prevent conformational changes on glycated albumin. Methods: Data mining is performed to obtain human serum albumin (HSA) (4K2C), glucose (79025), ASX (5281224), and metformin (4091). Data preparation used PyRx and Discovery Studio 2016 Client. PyRx is utilized for docking and analysis of receptor-ligand interactions with LigPlus and Discovery Studio 2016 Client. YASARA is used for molecular dynamics simulations with a running time of 15.000 ps. Results: A description of the glycated-HSA (gHSA) conformational changes that are bound to metformin has been successfully carried out. Changes that occur were unfolding and release of bonds in gHSA. Unfolding on gHSA includes the release of bonds between sites A and B. The root mean square deviation (RMSD) backbone value of metformin-gHSA shows a significant difference with gHSA at 8650 ps where gHSA showed 6.47 nm while the metformin-gHSA was 8.06 nm and continues to increase up to 15.72 nm at the end of the simulation. RMSD and root mean square fluctuation residues of gHSA which were interacted with ASX showed conditions close to normal HSA. In 11725 ps ASX-gHSA remained stable at 5.78 nm, whereas gHSA increased to 8.13 nm. gHSA at the end of the simulation showed a number of 9.052 nm while the normal HSA was 7.561 nm. Conclusion: This result indicated that ASX prevents gHSA from possible unfolding.


1989 ◽  
Vol 258 (1) ◽  
pp. 199-204 ◽  
Author(s):  
B Honoré ◽  
A O Pedersen

pH- and fatty acid-induced conformational changes in human serum albumin were investigated by fluorescence-energy transfer, determining the distance between Trp-214 and bound bilirubin at 25 degrees C. This distance changes significantly with the pH, being 2.52 +/- 0.01 nm at pH 6, 2.31 +/- 0.04 nm at pH 9, 2.13 +/- 0.07 nm at pH 11.0 and 2.77 nm at pH 11.9. The influence of different fatty acids on the distance was also determined. At pH 7.4 medium-chain fatty acids seem to increase this distance, whereas long-chain fatty acids, at low concentrations, decrease the distance between the two chromophores. The contraction of the protein carrying long-chain saturated fatty acids is even more pronounced at pH 9.


2011 ◽  
Vol 100 (9) ◽  
pp. 2293-2301 ◽  
Author(s):  
Matthias J.N. Junk ◽  
Hans W. Spiess ◽  
Dariush Hinderberger

Sign in / Sign up

Export Citation Format

Share Document