posted on 2025-02-05, 02:03authored byAixia Ma, Hong Wang, Huiyang Jia, Shuya Yu, Wenhui Zhu, Kongfang Yu, Ye Ma, Yuan Li, Jinyao Li
The nattokinase propeptide acts as an intramolecular
chaperone
that is essential for the correct folding of the mature peptide. Understanding
key catalytic regions and sites in this propeptide is crucial for
enhancing the nattokinase folding efficiency. Through bioinformatics
and enzyme activity screening, we pinpointed critical sites affecting
folding efficiency and identified mutants Y106V and A103T. In fermentation,
their crude enzyme activities reached 277.83 and 205.63% of those
of WT, respectively. Mutant Y106V exhibited a 19.2% increase in the
specific enzyme activity, improving both the folding efficiency and
peptide conformation. Molecular dynamics simulations elucidated the
catalytic changes in Y106V and A103T. Optimization of fermentation
processes for these mutants yielded nattokinase levels of 317.042
and 336.65 U/mL. This study lays a foundation for further research
on nattokinase propeptide function and modification.