Phylum-level studies of bacterial cutinases for unravelling enzymatic specificity toward PET degradation: an in silico approach

Braz J Microbiol. 2024 Sep;55(3):2385-2400. doi: 10.1007/s42770-024-01362-6. Epub 2024 May 15.

Abstract

The overwhelming use of PET plastic in various day-to-day activities led to the voluminous increase in PET waste and growing environmental hazards. A plethora of methods have been used that are associated with secondary pollutants. Therefore, microbial degradation of PET provides a sustainable approach due to its versatile metabolic diversity and capacity. The present work highlights the cutinase enzyme's role in PET degradation. This study focuses on the bacterial cutinases homologs screened from 43 reported phylum of bacteria. The reported bacterial cutinases for plastic degradation have been chosen as reference sequences, and 917 sequences have shown homology across the bacterial phyla. The dienelactone hydrolase (DLH) domain was identified for attaining specificity towards PET binding in 196 of 917 sequences. Various computational tools have been used for the physicochemical characterization of 196 sequences. The analysis revealed that most selected sequences are hydrophilic, extracellular, and thermally stable. Based on this analysis, 17 sequences have been further pursued for three-dimensional structure prediction and validation. The molecular docking studies of 17 selected sequences revealed efficient PET binding with the three sequences derived from the phylum Bacteroidota, the lowest binding energy of -5.9 kcal/mol, Armatimonadota, and Nitrososphaerota with -5.8 kcal/mol. The two enzyme sequences retrieved from the phylum Bacteroidota and Armatimonadota are metagenomically derived. Therefore, the present studies concluded that there is a high probability of finding cutinase homologs in various environmental resources that can be further explored for PET degradation.

Keywords: Cutinase; Environmental sustainability; Molecular docking; PET; Plastic degradation.

MeSH terms

  • Bacteria* / classification
  • Bacteria* / enzymology
  • Bacteria* / genetics
  • Bacteria* / metabolism
  • Bacterial Proteins* / chemistry
  • Bacterial Proteins* / genetics
  • Bacterial Proteins* / metabolism
  • Biodegradation, Environmental
  • Carboxylic Ester Hydrolases* / chemistry
  • Carboxylic Ester Hydrolases* / genetics
  • Carboxylic Ester Hydrolases* / metabolism
  • Computer Simulation
  • Molecular Docking Simulation*
  • Phylogeny
  • Polyethylene Terephthalates / chemistry
  • Polyethylene Terephthalates / metabolism
  • Substrate Specificity

Substances

  • cutinase
  • Carboxylic Ester Hydrolases
  • Bacterial Proteins
  • Polyethylene Terephthalates