Molecular docking studies and in vitro degradation of four aflatoxins (AFB_1, AFB_2, AFG_1, and AFG_2) by a recombinant laccase from Saccharomyces cerevisiae

摘要

Here, molecular docking simulation was used to predict and compare interactions between a recombinant Trametes sp. C30 laccase from Saccharomyces cerevisiae and four aflatoxins (AFB_1, AFB_2, AFG_1, and AFG_2) as well as their degradation at a molecular level. The computational result of docking simulation indicates that each of the aflatoxins tested can interact with laccase with a binding ability of AFB_1 ＞AFG_2＞AFG_1 ＞AFB_2. Simultaneously, it also demonstrated that aflatoxin B_1, B_2, G_1, G_2 may interact near the T1 copper center of the enzyme through H-bonds and hydrophobic interactions with amino acid residues His481 and Asn288; His481; Asn288, and Asp230; His481 and Asn288. Biological degradation test was performed in vitro in the presence of a recombinant laccase. Degradation increased as incubation time increased from 12 to 60 hr and the maximum degradation obtained for AFB_1, AFB_2, AFG_1, and AFG_2 was 90.33%, 74.23%, 85.24%, and 87.58%, respectively. Maximum degradation of aflatoxins was determined with a total activity 3 U laccase at 30 °C in 0.1 M phosphate buffer, pH 5.7 after 48-hr incubation. The experimental results are consistent with that of docking calculation on the biological degradation test of four aflatoxins by laccase.