In silico structural analysis and biochemical characterization of a novel PETase from Antarctic Streptomyces sp .

Polyethylene terephthalate (PET) is among the most prevalent plastic pollutants, with enzymatic degradation offering an eco-friendly alternative to conventional recycling methods. Here, we report the biochemical characterization and in silico analysis of a novel PET-degrading enzyme (SsPETase) isolated from Streptomyces sp. SsPETase exhibited optimal PET-degrading activity at elevated temperatures and under alkaline conditions, highlighting its potential for industrial applications. Using AlphaFold, we reliably predicted the enzyme's three-dimensional structure (pTM score = 0.96). Structural comparisons with IsPETase identified key catalytic residues, including a wobbling tryptophan near the active site, as promising targets for future enzyme engineering. Molecular dynamics simulations further revealed a substrate-dependent conformational shift between compact (inactive) and open (active) states. These findings provide deeper insights into the structure-function relationship of SsPETase and demonstrate the value of complementary computational approaches for the rational design of next-generation plastic-degrading enzymes.