Biochemical and biophysical characterization of a peroxiredoxin selected from the Delftia sp., a...

Peroxiredoxins (Prxs) are thiol-dependent peroxidases that play central roles in redox homeostasis and oxidative stress protection. Here, we report the biochemical and biophysical characterization of a peroxiredoxin (Bcp_00857; whose acronym Bcp derives from the subfamily Bacterioferritin Comigratory Protein - BCP) from Delftia sp., a bacterium previously identified as capable of polyethylene (PE) biodegradation. Recombinant Bcp_00857 was successfully expressed in E. coli and purified to homogeneity. The enzyme exhibited high activity in hydrogen peroxide (H₂O₂) reduction across a broad temperature range (10-40 °C) and at neutral to alkaline pH (7-9), and retained > 50% of its activity after seven days at 30 °C. Kinetic parameters for Bcp_00857 revealed an apparent V_max of 18.39 µM.min⁻¹ and an apparent K_m of 79.9 µM for H₂O₂ reduction. The prediction of its three-dimensional structure was performed using the Alphafold2 program, suggesting high model quality according to validation system. Biophysical analysis by circular dichroism (CD) demonstrated that temperature and oxidative treatments influenced the secondary structure of Bcp_00857. Our findings provide the first enzymatic and structural characterization of a peroxiredoxin from the PE-degrader Delftia sp., establishing a foundation for future work on its biological role and potential relevance to adaptive responses during PE metabolism.