posted on 2024-02-01, 19:03authored byJinghao Shi, Fred Mwabulili, Yanli Xie, Yuhui Yang, Shumin Sun, Qian Li, Weibin Ma, Hang Jia
Zearalenone (ZEN) is a widespread mycotoxin that causes
serious
damage to animal husbandry and poses a threat to human health. A screen
of ZEN-degrading soil bacteria yielded Bacillus subtilis YT-4, which yielded 80% ZEN degradation after 6 h and 95% after
36 h. The gene sequence encoding the degradative enzyme ZENY was mined
from the genome of YT-4 and expressed in yeast. ZENY is an α/β-hydrolase
with an optimal enzyme activity at 37 °C and pH 8. By breaking
the lactone ring of ZEN, it produces ZENY-C18H24O5 with a molecular weight of 320.16 g/mol. Sequence comparison
and molecular docking analyses identified the catalytic ZENY triad
99S-245H-123E and the primary ZEN-binding mode within the hydrophobic
pocket of the enzyme. To improve the thermal stability of the enzyme
for industrial applications, we introduced a mutation at the N-terminus,
specifically replacing the fifth residue N with V, and achieved a
25% improvement in stability at 45 °C. These findings aim to
achieve ZEN biodegradation and provide insight into the structure
and function of ZEN hydrolases.