A Novel Polyester Hydrolase From the Marine BacteriumPseudomonas aestusnigri -Structural and Functional Insights.
Bollinger, A., Thies, S., Knieps-Grunhagen, E., Gertzen, C., Kobus, S., Hoppner, A., Ferrer, M., Gohlke, H., Smits, S.H.J., Jaeger, K.E.(2020) Front Microbiol 11: 114-114
- PubMed: 32117139 
- DOI: https://doi.org/10.3389/fmicb.2020.00114
- Primary Citation of Related Structures:  
6SBN, 6SCD - PubMed Abstract: 
Biodegradation of synthetic polymers, in particular polyethylene terephthalate (PET), is of great importance, since environmental pollution with PET and other plastics has become a severe global problem. Here, we report on the polyester degrading ability of a novel carboxylic ester hydrolase identified in the genome of the marine hydrocarbonoclastic bacterium Pseudomonas aestusnigri VGXO14 T . The enzyme, designated PE-H, belongs to the type IIa family of PET hydrolytic enzymes as indicated by amino acid sequence homology. It was produced in Escherichia coli , purified and its crystal structure was solved at 1.09 Å resolution representing the first structure of a type IIa PET hydrolytic enzyme. The structure shows a typical α/β-hydrolase fold and high structural homology to known polyester hydrolases. PET hydrolysis was detected at 30°C with amorphous PET film (PETa), but not with PET film from a commercial PET bottle (PETb). A rational mutagenesis study to improve the PET degrading potential of PE-H yielded variant PE-H (Y250S) which showed improved activity, ultimately also allowing the hydrolysis of PETb. The crystal structure of this variant solved at 1.35 Å resolution allowed to rationalize the improvement of enzymatic activity. A PET oligomer binding model was proposed by molecular docking computations. Our results indicate a significant potential of the marine bacterium P. aestusnigri for PET degradation.
Organizational Affiliation: 
Institute of Molecular Enzyme Technology, Heinrich Heine University Düsseldorf, Jülich, Germany.