Structure and function of the metagenomic plastic-degrading polyester hydrolase PHL7 bound to its product
Authors/Creators
- 1. Leipzig University
- 2. Leipzig University Medical School
- 3. University of Parma
Description
The recently discovered metagenomic-derived polyester hydrolase PHL7 is
able to efficiently degrade amorphous polyethylene terephthalate (PET) in
post-consumer plastic waste. We present the cocrystal structure of this
hydrolase with its hydrolysis product terephthalic acid and elucidate the
influence of 17 single mutations on the PET-hydrolytic activity and thermal
stability of PHL7. The substrate-binding mode of terephthalic acid is similar to
that of the thermophilic polyester hydrolase LCC and deviates from the
mesophilic IsPETase. The subsite I modifications L93F and Q95Y, derived from
LCC, increased the thermal stability, while exchange of H185S, derived from
IsPETase, reduced the stability of PHL7. The subsite II residue H130 is suggested
to represent an adaptation for high thermal stability, whereas L210
emerged as the main contributor to the observed high PET-hydrolytic activity.
Variant L210T showed significantly higher activity, achieving a degradation
rate of 20 μmh−1 with amorphous PET films.