Interaction of the Fungicide Tebuconazole with Human Serum Albumin: A Preliminary Study

Abstract The interactions between the fungicide tebuconazole and human serum albumin were investigated using fluorescence and circular dichroism spectroscopies. The experimental results showed that the fluorescence quenching of the protein by the tebuconazole molecule was a result of the formation of a ligand-protein complex with a binding constant of 8.51×103 l.mol−1 and the number of binding sites in the macromolecule was close to 1. These findings demonstrated the fact that although the binding affinity of tebuconazole to the protein may be slight, it was very similar to other triazole fungicides. In addition, tebuconazole stabilized the α-helical secondary structure of the human serum albumin due to the increase of the α-content in the protein macromolecule.

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Determination of the number of binding sites and the mechanism of quenching about the bilirubin on human serum albumin by spectroscopic method

Clinical Biochemistry ◽

10.1016/j.clinbiochem.2011.08.908 ◽

2011 ◽

Vol 44 (13) ◽

pp. S262

Author(s):

Akram Hosenzadeh ◽

Jamshid Chamani ◽

Mohsen Gharanfoli

Keyword(s):

Human Serum Albumin ◽

Serum Albumin ◽

Human Serum ◽

Binding Sites ◽

Spectroscopic Method ◽

Number Of Binding Sites

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Influence of mutations caused by radiation exposure on the bilirubin binding sites of human serum albumin

Proceedings of the National Academy of Sciences of Belarus Medical series ◽

10.29235/1814-6023-2021-18-1-46-57 ◽

2021 ◽

Vol 18 (1) ◽

pp. 46-57

Author(s):

V. V. Poboinev ◽

V. V. Khrustalev ◽

A. N. Stojarov ◽

T. A. Khrustaleva

Keyword(s):

Amino Acid ◽

Secondary Structure ◽

Human Serum Albumin ◽

Serum Albumin ◽

Radiation Exposure ◽

Human Serum ◽

Binding Sites ◽

Amino Acid Substitutions ◽

Amino Acid Residues ◽

Bilirubin Binding

In this article we analyze the bilirubin binding sites of human serum albumin from the point of view of the secondary structure instability, as well as the effect of amino acid substitutions caused by radiation exposure on the ability of albumin to bind bilirubin-IX-alpha. Based on calculations of binding energy and inhibition constants of bilirubin-albumin complexes before and after the amino acid substitutions, it was found that amino acid substitutions have different effects on the ability of human serum albumin to bind bilirubin. Amino acid substitutions Asp269-Gly269 (Nagasaki-1), Glu354-Lys354 (Hiroshima-1), Asp375-Asn375 (Nagasaki-2) reduce the binding free energy of bilirubin with human serum albumin, and the amino acid substitutions His3-Gln3 (Nagasaki-3) and Glu382-Lys382 (Hiroshima-2) increase it during molecular docking with the corresponding areas of the protein surface. The inhibition constants are significantly higher than with known binding sites. In general, mutations caused by radiation exposure cannot effect on bilirubin binding sites of human serum albumin, since the amino acid residues that are replaced do not interact with the amino acid residues from the binding sites (Leu115, Arg117, Phe134, Tyr138, Ile142, Phe149, Phe157, Tyr161, Arg186, Lys190, Lys240, Arg222). All amino acid residues from known binding sites are located in stable elements of the secondary structure of human serum albumin.The data obtained are important for understanding the impact of radiation exposure on the development of bilirubin encephalopathy in the population of the Chernobyl region and Japan.

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The Effect of Tigecycline on the Binding of Fluoroquinolones to Human Serum Albumin

Serbian Journal of Experimental and Clinical Research ◽

10.1515/sjecr-2017-0006 ◽

2018 ◽

Vol 19 (1) ◽

pp. 17-25 ◽

Cited By ~ 1

Author(s):

Ratomir M. Jelic ◽

Stefan D. Stojanovic ◽

Jelena D. Beric ◽

Jadranka Odovic

Keyword(s):

Human Serum Albumin ◽

Fluorescence Quenching ◽

Serum Albumin ◽

Human Serum ◽

Binding Sites ◽

Interaction Mechanism ◽

Binding Constants ◽

Binding Mode ◽

Binding Ability ◽

Free Plasma

AbstractThe co-administration of several drugs in multidrug therapy may alter the binding of each drug to human serum albumin (HSA) and, thus, their pharmacology effect. Therefore, in this study, the interaction mechanism between HSA and two fluoroquinolones (FQs), sparfloxacin (SPF) and levofloxacin (LVF), was investigated using fluorescence and absorption methods in the absence and presence of the competing drugtigecycline (TGC). The the UV-Vis and fluorescence spectroscopy results showed that the fluorescence quenching of HSA was a result of the formation of the HSA-SPF and HSA-LVF complexes. The fluorescence quenching of HSA-TGC revealed that tigecycline can regulate the binding sites, binding mode and binding affinity of fluoroquinolones. The binding constants (KA) and binding sites (n) of the interaction systems were calculated. The results confirmed that the KA values of the HSA-FQ system decreased in the presence of TGC, indicating that TGC can affect the binding ability of FQ for HSA. This interaction may increase the free plasma concentration of unbound FQ and enhance their pharmacology effect.

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Truncated human serum albumin retains general anaesthetic binding activity

Biochemical Journal ◽

10.1042/bj20041224 ◽

2005 ◽

Vol 388 (1) ◽

pp. 39-45 ◽

Cited By ~ 16

Author(s):

Renyu LIU ◽

Jinsheng YANG ◽

Chung-Eun HA ◽

Nadhipuram V. BHAGAVAN ◽

Roderic G. ECKENHOFF

Keyword(s):

Secondary Structure ◽

Human Serum Albumin ◽

Serum Albumin ◽

Human Serum ◽

Binding Sites ◽

Expression System ◽

Titration Calorimetry ◽

General Anaesthetic ◽

Solution Studies ◽

Domain 3

Multiple binding sites for anaesthetics in HSA (human serum albumin) make solution studies difficult to interpret. In the present study, we expressed the wild-type HSA domain 3 (wtHSAd3), a peptide with two known anaesthetic binding sites in a yeast expression system. We also expressed a site-directed mutant of domain 3 (Y411Wd3). The stability and secondary structure of the constructed fragments were determined by HX (hydrogen–tritium exchange) and CD spectroscopy. The binding of two general anaesthetics, 2-bromo-2-chloro-1,1,1-trifluoroethane and propofol, to wtHSAd3 and Y411Wd3 was determined using isothermal titration calorimetry, HX and intrinsic tryptophan fluorescence quenching. Although the expressed fragments are less stable than intact wtHSA as indicated by both CD and HX, they retain the secondary structure and anaesthetic-binding characteristics of an intact HSA molecule, but with fewer binding sites. Y411Wd3 had decreased affinity for propofol but not for 2-bromo-2-chloro-1,1,1-trifluoroethane, consistent with steric hindrance. Retention of structural features and anaesthetic binding properties with fewer binding sites in this truncated protein provide feasibility for using scaled-down models of otherwise intractable systems to gain an understanding of anaesthetic binding requirements and binding–stability relationships.

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