Structural Insights into the Expanded Substrate Scope of a Cysteine-Dependent Hydrolase from Rhodococcus opacus for Polyethylene, Polypropylene, and Polystyrene Biodegradation
Abstract
Microplastic pollution from homopolymers such as polypropylene (PP), polystyrene (PS), and polyethylene (PE) poses growing health and environmental concerns, highlighting the need for robust polymer-degrading biocatalysts. We previously identified a naturally occurring cysteine-dependent hydrolase (CsdH) from Rhodococcus opacus, featuring a unique Cys160-Lys127-Asp39 catalytic triad and providing a novel mechanism for polyethylene terephthalate (PET) degradation. In this study, we have determined crystal structures of CsdH in complex with PP, PS, PE, and styrene and demonstrated the potential of the enzyme to directly degrade these homopolymers into their respective low molecular weight degradation products using LC-MS. Structural analysis reveals that the enzyme retains a conserved principal access tunnel while undergoing subtle substrate-dependent changes to accommodate different substrates. The enzyme exhibited broad plastic degradation activity with the highest weight loss observed for PE, followed by PP and PS. SEM analysis reveals surface roughness, cracks and grooves, confirming polymer degradation. Further, these results corroborate through FTIR and TGA analysis. These findings establish a strong foundation for enzyme engineering and aim at developing efficient microplastic degradation.
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BibTeX
@misc{aggarwal2026structural,
title = {{Structural Insights into the Expanded Substrate Scope of a Cysteine-Dependent Hydrolase from Rhodococcus opacus for Polyethylene, Polypropylene, and Polystyrene Biodegradation}},
author = {S. Aggarwal and S. Singh and A. Kayastha and D. Aggarwal and K. Jangid and M. Shakib and D. Singh and A. K. Sharma and P. Kumar},
howpublished = {bioRxiv},
year = {2026},
month = oct,
doi = {10.64898/2026.10.07.757487},
url = {https://www.biorxiv.org/content/10.64898/2026.10.07.757487v1},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - Structural Insights into the Expanded Substrate Scope of a Cysteine-Dependent Hydrolase from Rhodococcus opacus for Polyethylene, Polypropylene, and Polystyrene Biodegradation
AU - S. Aggarwal
AU - S. Singh
AU - A. Kayastha
AU - D. Aggarwal
AU - K. Jangid
AU - M. Shakib
AU - D. Singh
AU - A. K. Sharma
AU - P. Kumar
PY - 2026
DA - 2026/10/07
PB - bioRxiv
DO - 10.64898/2026.10.07.757487
UR - https://www.biorxiv.org/content/10.64898/2026.10.07.757487v1
AB - Microplastic pollution from homopolymers such as polypropylene (PP), polystyrene (PS), and polyethylene (PE) poses growing health and environmental concerns, highlighting the need for robust polymer-degrading biocatalysts. We previously identified a naturally occurring cysteine-dependent hydrolase (CsdH) from Rhodococcus opacus, featuring a unique Cys160-Lys127-Asp39 catalytic triad and providing a novel mechanism for polyethylene terephthalate (PET) degradation. In this study, we have determined crystal structures of CsdH in complex with PP, PS, PE, and styrene and demonstrated the potential of the enzyme to directly degrade these homopolymers into their respective low molecular weight degradation products using LC-MS. Structural analysis reveals that the enzyme retains a conserved principal access tunnel while undergoing subtle substrate-dependent changes to accommodate different substrates. The enzyme exhibited broad plastic degradation activity with the highest weight loss observed for PE, followed by PP and PS. SEM analysis reveals surface roughness, cracks and grooves, confirming polymer degradation. Further, these results corroborate through FTIR and TGA analysis. These findings establish a strong foundation for enzyme engineering and aim at developing efficient microplastic degradation.
ER -