Structure of MHETase from Ideonella sakaiensis

Experimental Data Snapshot

  • Resolution: 1.90 Å
  • R-Value Free: 0.205 
  • R-Value Work: 0.185 
  • R-Value Observed: 0.186 

wwPDB Validation   3D Report Full Report

This is version 1.4 of the entry. See complete history


Characterization and engineering of a two-enzyme system for plastics depolymerization.

Knott, B.C.Erickson, E.Allen, M.D.Gado, J.E.Graham, R.Kearns, F.L.Pardo, I.Topuzlu, E.Anderson, J.J.Austin, H.P.Dominick, G.Johnson, C.W.Rorrer, N.A.Szostkiewicz, C.J.Copie, V.Payne, C.M.Woodcock, H.L.Donohoe, B.S.Beckham, G.T.McGeehan, J.E.

(2020) Proc Natl Acad Sci U S A 117: 25476-25485

  • DOI: https://doi.org/10.1073/pnas.2006753117
  • Primary Citation of Related Structures:  
    6QZ1, 6QZ2, 6QZ3, 6QZ4

  • PubMed Abstract: 

    Plastics pollution represents a global environmental crisis. In response, microbes are evolving the capacity to utilize synthetic polymers as carbon and energy sources. Recently, Ideonella sakaiensis was reported to secrete a two-enzyme system to deconstruct polyethylene terephthalate (PET) to its constituent monomers. Specifically, the I. sakaiensis PETase depolymerizes PET, liberating soluble products, including mono(2-hydroxyethyl) terephthalate (MHET), which is cleaved to terephthalic acid and ethylene glycol by MHETase. Here, we report a 1.6 Å resolution MHETase structure, illustrating that the MHETase core domain is similar to PETase, capped by a lid domain. Simulations of the catalytic itinerary predict that MHETase follows the canonical two-step serine hydrolase mechanism. Bioinformatics analysis suggests that MHETase evolved from ferulic acid esterases, and two homologous enzymes are shown to exhibit MHET turnover. Analysis of the two homologous enzymes and the MHETase S131G mutant demonstrates the importance of this residue for accommodation of MHET in the active site. We also demonstrate that the MHETase lid is crucial for hydrolysis of MHET and, furthermore, that MHETase does not turnover mono(2-hydroxyethyl)-furanoate or mono(2-hydroxyethyl)-isophthalate. A highly synergistic relationship between PETase and MHETase was observed for the conversion of amorphous PET film to monomers across all nonzero MHETase concentrations tested. Finally, we compare the performance of MHETase:PETase chimeric proteins of varying linker lengths, which all exhibit improved PET and MHET turnover relative to the free enzymes. Together, these results offer insights into the two-enzyme PET depolymerization system and will inform future efforts in the biological deconstruction and upcycling of mixed plastics.

  • Organizational Affiliation

    Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO 80401.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Mono(2-hydroxyethyl) terephthalate hydrolase
A, B, C, D, E
A, B, C, D, E, F, G, H, I, J
611Piscinibacter sakaiensisMutation(s): 0 
Gene Names: ISF6_0224
Find proteins for A0A0K8P8E7 (Ideonella sakaiensis (strain NBRC 110686 / TISTR 2288 / 201-F6))
Explore A0A0K8P8E7 
Go to UniProtKB:  A0A0K8P8E7
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupA0A0K8P8E7
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.90 Å
  • R-Value Free: 0.205 
  • R-Value Work: 0.185 
  • R-Value Observed: 0.186 
  • Space Group: P 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 110.49α = 83.09
b = 135.63β = 67.91
c = 138.15γ = 67.57
Software Package:
Software NamePurpose
XDSdata reduction
SCALAdata scaling

Structure Validation

View Full Validation Report

Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
Biotechnology and Biological Sciences Research CouncilUnited KingdomBB/P011918/1

Revision History  (Full details and data files)

  • Version 1.0: 2020-09-30
    Type: Initial release
  • Version 1.1: 2020-10-07
    Changes: Database references
  • Version 1.2: 2020-10-14
    Changes: Data collection, Database references
  • Version 1.3: 2020-10-21
    Changes: Database references
  • Version 1.4: 2024-01-24
    Changes: Data collection, Database references, Refinement description