Xu_2025_Int.J.Biol.Macromol_286_138531

Recently, how could microbial lactonase react to the mycotoxin zearalenone (ZEN) and its derivatives such as alpha-zearalenol (alpha-ZOL) is still unclear, resulting in limited applications. In this study, the interaction networks of residues near the beta6-alpha6 region in lactonase from Monosporascus sp. GIB2 (ZENM) were analyzed. As a result, the residue M157 in the beta6-alpha6 region was found significant to the specificity of ZENM, and two mutants including ZENM(M157V) and ZENM(M157I) that exhibited higher degradation activity than the wild-type (WT) against alpha-ZOL was achieved. The molecular dynamics simulation showed that the binding free energy of ZENM(M157V) and ZENM(M157I) was -38.68 and -40.84 Kcal/mol for alpha-ZOL, much lower than the wild-type enzyme (-33.03 Kcal/mol). Moreover, approximately a 54 degrees torsion of the C6' hydroxyl group in alpha-ZOL was presented in mutants ZENM(M157V) and ZENM(M157I) conformation, resulting in a shorter distance between the catalytic pocket and alpha-ZOL.