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A New Screening Method for the Directed Evolution of Thermostable Bacteriolytic Enzymes
Published on: November 7, 2012
Structural and functional characterization of thermostable EstS1 esterase for BHET degradation
Shalja Verma1, Divya Aggarwal1, Meet Ashar1
1Department of Biosciences and Bioengineering, IIT Roorkee, Roorkee, Uttarakhand 247667, India.
Journal of Structural Biology
|June 9, 2026
Summary
This study reveals how the thermostable EstS1 esterase degrades bis(2-hydroxyethyl) terephthalate (BHET), a key PET plastic intermediate. Structural insights show EstS1’s potential for efficient plastic degradation technologies.
Area of Science:
- Biochemistry
- Structural Biology
- Enzyme Engineering
Background:
- Enzymatic plastic degradation faces limitations due to enzyme instability and low efficiency.
- Polyethylene terephthalate (PET) degradation is a significant environmental challenge.
Purpose of the Study:
- To elucidate the structural and functional characteristics of the thermostable EstS1 esterase from Sulfobacillus acidophilus DSM10332.
- To investigate the degradation mechanism of bis(2-hydroxyethyl) terephthalate (BHET) by EstS1.
Main Methods:
- Co-crystal structure determination of wild-type EstS1 and a Ser154Ala mutant with BHET.
- Kinetic analyses of BHET degradation.
- Molecular dynamics (MD) simulations.
Main Results:
- EstS1 binds BHET and its degradation products (MHET, ethylene glycol) in its active site.
- The hydrophobic cavity 1, formed by the cap domain, is crucial for substrate binding and catalysis.
- EstS1 efficiently degraded 75% of BHET within 1 hour, producing MHET and terephthalate, indicating consecutive ester bond cleavage.
- MD simulations confirmed stable EstS1-BHET interactions.
Conclusions:
- EstS1 esterase exhibits a remarkable ability to consecutively cleave two ester bonds in BHET.
- Structural insights into the EstS1-BHET interaction mechanism are provided.
- EstS1 shows significant potential for direct conversion of BHET to terephthalate, supporting future enzyme engineering for PET degradation technologies.
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