Improving the Catalytic Activity and Thermostability of FAST-PETase with a Multifunctional Short Peptide

Previous reports indicated that self-assembling amphipathic peptide S1v1 (AEAEAHAH)₂ significantly enhances the soluble expression, thermostability, and activity of the target proteins when fused to them. In order to obtain high-efficiency enzymes for the large-scale degradation of polyethylene terephthalate (PET), this multifunctional peptide was fused to the N- and C-terminus of FAST-PETase, a variant of <i>Ideonella sakaiensis</i> PETase (<i>Is</i>PETase), with a PT-linker (TTVTTPQTS) harbored between the target protein and the multifunctional peptide. Consistent with previous reports, S1v1 increased the solubility of FAST-PETase slightly. Moreover, it increased the activity of FAST-PETase dramatically. The amount of terephthalic acid (TPA) and mono(2-hydroxyethyl) terephthalic acid (MHET) released from PET substrate after 24 h of digestion at 50°C by fusion enzymes bearing N- and C-terminal S1v1 tag was approximately 2.9- and 4.6-fold that of FAST-PETase, respectively. Furthermore, the optimal temperature and thermostability of the fusion proteins increased in comparison with FAST-PETase. The present study provides a novel strategy to improve the depolymerization efficiency of FAST-PETase.