Fusion of binding domains to Thermobifida cellulosilytica cutinase to tune sorption characteristics and enhancing PET hydrolysis

Biomacromolecules. 2013 Jun 10;14(6):1769-76. doi: 10.1021/bm400140u. Epub 2013 May 29.

Abstract

A cutinase from Thermomyces cellullosylitica (Thc_Cut1), hydrolyzing the synthetic polymer polyethylene terephthalate (PET), was fused with two different binding modules to improve sorption and thereby hydrolysis. The binding modules were from cellobiohydrolase I from Hypocrea jecorina (CBM) and from a polyhydroxyalkanoate depolymerase from Alcaligenes faecalis (PBM). Although both binding modules have a hydrophobic nature, it was possible to express the proteins in E. coli . Both fusion enzymes and the native one had comparable kcat values in the range of 311 to 342 s(-1) on pNP-butyrate, while the catalytic efficiencies kcat/Km decreased from 0.41 s(-1)/ μM (native enzyme) to 0.21 and 0.33 s(-1)/μM for Thc_Cut1+PBM and Thc_Cut1+CBM, respectively. The fusion enzymes were active both on the insoluble PET model substrate bis(benzoyloxyethyl) terephthalate (3PET) and on PET although the hydrolysis pattern was differed when compared to Thc_Cut1. Enhanced adsorption of the fusion enzymes was visible by chemiluminescence after incubation with a 6xHisTag specific horseradish peroxidase (HRP) labeled probe. Increased adsorption to PET by the fusion enzymes was confirmed with Quarz Crystal Microbalance (QCM-D) analysis and indeed resulted in enhanced hydrolysis activity (3.8× for Thc_Cut1+CBM) on PET, as quantified, based on released mono/oligomers.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actinomycetales / enzymology*
  • Adsorption
  • Binding Sites
  • Carboxylic Ester Hydrolases / chemistry
  • Carboxylic Ester Hydrolases / genetics
  • Carboxylic Ester Hydrolases / metabolism*
  • Cloning, Molecular
  • Electrophoresis, Polyacrylamide Gel
  • Hydrolysis
  • Models, Molecular
  • Polyethylene Terephthalates / chemistry*
  • Polyethylene Terephthalates / metabolism
  • Recombinant Fusion Proteins / chemistry
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism*

Substances

  • Polyethylene Terephthalates
  • Recombinant Fusion Proteins
  • Carboxylic Ester Hydrolases
  • cutinase