STRUCTURAL AND BIOPHYSICAL STUDIES OF A CUTINASE OF ANTARTIC ORIGIN

Poly (ethylene terephthalate), widely known as PET, is a widely used plastic due to its versatility. However, the low recycling rate of this material has contributed to environmental problems, making it a target of studies focused on bioremediation. In 2016, the first enzyme capable of degrading PET, PETase, was identified, isolated from the bacterium Ideonella sakaiensis. Since then, research in this area has advanced, but studies on the activity of PETases at low temperatures are still scarce. To explore this gap, metagenomic analyses were performed on surface waters from Antarctica, resulting in the isolation of 10 potential PETases. Among them, metaG7 demonstrated cutinase activity at low temperatures. To study this enzyme, the recombinant DNA technique was used, with expression in E. coli. Purification was performed by nickel column chromatography, followed by molecular exclusion. Subsequently, metaG7 was subjected to protein crystallography and X-ray diffraction analysis, which allowed the determination of its structure with a resolution of 2.9 Å. Structural analyses revealed relevant differences in the sequences and structures in relation to homologous enzymes, which can serve as a basis for future studies on the activity of PETases in low-temperature environments.