Interaction of aflatoxin G₁ with free DNA in vitro and possibility of its application in removing aflatoxin G₁

Abstract

The present study sought to evaluate the interaction between aflatoxin G₁ and free DNA in vitro through different analytical techniques. The UV–visible spectra results showed that the structure of DNA might be changed with a new aflatoxin G₁-DNA complex forming, which indicated that the interacting mode between them was the intercalating mode. The DNA melting temperature increased by 12.80 °C, suggesting that the DNA double helix structure was more compact and stable through intercalation. The circular dichroism (CD) spectra results indicated that the interaction of aflatoxin G₁ with DNA induced the DNA base stacking changes. The results of agarose gel electrophoresis and fluorescence microscope further verified that the interacting mode between aflatoxin G₁ and DNA was intercalation mode. According to the fluorescence spectrum data, the binding constant was calculated 6.24 × 10⁴ L·mol⁻¹. The thermodynamic results demonstrated that the reaction of aflatoxin G₁ intercalating to DNA was a spontaneous reaction. The elimination results suggested that aflatoxin G₁ could be enriched and removed by DNA intercalation through magnetic beads separation, with the removal efficiency of 93.73%. The study results would provide a theoretical basis for establishing a new aflatoxin removal method based on DNA intercalation.

Keywords:

• Aflatoxin G₁
• DNA
• spectroscopy
• interaction
• removal efficiency

Additional information

Funding

This work was supported by the National Natural Science Foundation of China (Grant number 21966008) and the Guangxi Natural Science Foundation of China (Grant numbers 2018GXNSFDA281030 and 2020GXNSFAA159021).