Improvement of the fibrinolytic activity, acid resistance and thermostability of nattokinase by surface charge engineering

Maggot Kinase and Natural Thrombolytic Proteins

“…NK has a molecular weight of 27.7 kDa, a pI within the 8.6–8.9 range, 52 an optimal reaction pH of 7.0, and exhibits a relatively stable enzymatic activity between pH 6.0 and 9.0; 53 it has an optimal reaction temperature of 40 °C. 54 It is 1.36 times more active than UK and can induce the production of fibrinolytic enzymes through facilitating t-PA activity for thrombus and fibronectin degradation, making it a well-established natural thrombolytic enzyme in early research. 55 The gene encoding NK has a sequence length of 1473 bp, 56 − 58 and contains three parts and 381 amino acids.…”

Enhanced Thermostability of Nattokinase by Computation-Based Rational Redesign of Flexible Regions

“…It utilizes computer simulations and bioinformatics technology to obtain data on the structure, free energy, interaction entropy, interaction enthalpy, and other related properties of protein molecules through algorithms such as quantum mechanics, molecular docking, and molecular dynamics (MD) simulations. , This allows the establishment of small mutation libraries with a high accuracy. Liu et al combined protein surface charge engineering, sequence alignment, and a literature-based approach to successfully identify a mutant Q59E that enhances nattokinase enzyme activity; Li et al created a mutant K12D with improved fibrinolytic activity and mutants S33T, R45E, and T174 V with enhanced stability using computer-aided prediction and semirational design strategies; , and Luo et al generated mutant M4 by modifying the flexible region of nattokinase, resulting in a 20.7-fold increase in half-life and a 2-fold increase in fibrinolytic activity . However, in some cases, these strategies may not be effective due to the limited availability of relevant studies on protein sequence–structure–function relationships.…”