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Toxins (Basel). 2017 Oct 25;9(11). pii: E339. doi: 10.3390/toxins9110339.

Investigation of Non-Covalent Interactions of Aflatoxins (B1, B2, G1, G2, and M1) with Serum Albumin.

Author information

1
Department of Pharmacology, Faculty of Pharmacy, University of Pécs, Szigeti út 12, Pécs H-7624, Hungary. poor.miklos@pte.hu.
2
Department of Pharmacology and Pharmacotherapy, Medical School, University of Pécs, Szigeti út 12, Pécs H-7624, Hungary. monibalint18@gmail.com.
3
Department of Pharmacology and Pharmacotherapy, Medical School, University of Pécs, Szigeti út 12, Pécs H-7624, Hungary. csabahete@yahoo.com.
4
Department of Pharmacology, Faculty of Pharmacy, University of Pécs, Szigeti út 12, Pécs H-7624, Hungary. goderbea@freemail.hu.
5
Department of General and Physical Chemistry, University of Pécs, Ifjúság útja 6, Pécs H-7624, Hungary. kunsagi@gamma.ttk.pte.hu.
6
János Szentágothai Research Center, Ifjúság útja 20, Pécs H-7624, Hungary. kunsagi@gamma.ttk.pte.hu.
7
János Szentágothai Research Center, Ifjúság útja 20, Pécs H-7624, Hungary. koszegi.tamas@pte.hu.
8
Department of Laboratory Medicine, University of Pécs, Ifjúság útja 13, Pécs H-7624, Hungary. koszegi.tamas@pte.hu.
9
Department of General and Physical Chemistry, University of Pécs, Ifjúság útja 6, Pécs H-7624, Hungary. blemli@gamma.ttk.pte.hu.
10
János Szentágothai Research Center, Ifjúság útja 20, Pécs H-7624, Hungary. blemli@gamma.ttk.pte.hu.

Abstract

Aflatoxins are widely spread mycotoxins produced mainly by Aspergillus species. Consumption of aflatoxin-contaminated foods and drinks causes serious health risks for people worldwide. It is well-known that the reactive epoxide metabolite of aflatoxin B1 (AFB1) forms covalent adducts with serum albumin. However, non-covalent interactions of aflatoxins with human serum albumin (HSA) are poorly characterized. Thus, in this study the complex formation of aflatoxins was examined with HSA applying spectroscopic and molecular modelling studies. Our results demonstrate that aflatoxins form stable complexes with HSA as reflected by binding constants between 2.1 × 10⁴ and 4.5 × 10⁴ dm³/mol. A binding free energy value of -26.90 kJ mol-1 suggests a spontaneous binding process between AFB1 and HSA at room-temperature, while the positive entropy change of 55.1 JK-1 mol-1 indicates a partial decomposition of the solvation shells of the interacting molecules. Modeling studies and investigations with site markers suggest that Sudlow's Site I of subdomain IIA is the high affinity binding site of aflatoxins on HSA. Interaction of AFB1 with bovine, porcine, and rat serum albumins was also investigated. Similar stabilities of the examined AFB1-albumin complexes were observed suggesting the low species differences of the albumin-binding of aflatoxins.

KEYWORDS:

aflatoxin B1; aflatoxins; albumin-ligand interaction; fluorescence spectroscopy; serum albumin

PMID:
29068381
PMCID:
PMC5705954
DOI:
10.3390/toxins9110339
[Indexed for MEDLINE]
Free PMC Article

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