Difference between revisions of "Part:BBa K4275009"
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The 3D structure of MHETase consists of a catalytic domain and an extensive lid domain[1]. The catalytic domain adopts the α/β-hydrolase fold typical of a serine hydrolase, with an active site consist the catalytic triad Ser225, Asp492, and His528, which shows significant structural conservation compared to PETase. The lid domain partially covers the active site, hinders its capability to bind with PET fiber, and harbors a well-coordinated calcium cation[1].
 
The 3D structure of MHETase consists of a catalytic domain and an extensive lid domain[1]. The catalytic domain adopts the α/β-hydrolase fold typical of a serine hydrolase, with an active site consist the catalytic triad Ser225, Asp492, and His528, which shows significant structural conservation compared to PETase. The lid domain partially covers the active site, hinders its capability to bind with PET fiber, and harbors a well-coordinated calcium cation[1].
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===Characterization===
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<b>PET degradation</b>
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The degradation of PET polymers using an enzymatic approach requires the synergetic functions of PETase and MHETase, producing terephthalic acids and ethylene glycol by hydrolytic cleavages (Fig.2A). We constructed E. coli expression vectors for the production of PETase and MHETase that can be induced by IPTG (Fig.2B). The production of the proteins was verified by SDS-PAGE analysis (Fig.2C).
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[[Image:GreatBay SCIE--Part Fig7.png|thumbnail|750px|center|'''Figure 2:'''
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Fig.2 FAST-PETase expression (A) Metabolic pathway of PET degradation, PETase catalyzes the cleavage of PET into MHET (mono-2-hydroxyethyl terephthalate) and EG (Ethylene glycol). (B) Genetic circuit constructions of FAST-PETase and FAST-PETase-t with type I dockerin fused to anchor the enzyme subunit onto the cellulosome complex. (C) SDS-page analysis for PETase 5 and PETase 5-t (D) The PH values of different samples of PET degraded by PETases either fused or not fused with type I dockerin domain. ]]
  
  

Revision as of 15:29, 12 October 2022


MHETase

As the second enzyme of the PET degradation two-enzyme system found in Ideonella sakaiensis, the MHETase catalyzes the cleavage of the ester bond in MHET(Monohydroxyethyl terephthalate) and liberates the final products of PET degradation - EG(ethylene glycol) and TPA(terephthalic acid) into the solution[1]. The MHETase amino acid sequence used in this experiment is the same with the wild-type MHETase (GenBank Accession number: GAP38911.1). The enzyme MHETase works in synergy with PETase, the first enzyme in the two-enzyme PET degradation system found in Ideonella sakaiensis - a PET-degrading and assimilating strain of bacteria isolated from a water treatment plant.

GreatBay SCIE--3D MHETase.png

Figure 1 The 3D structure of the protein predicted by Alphafold2.

Usage and Biology

The 3D structure of MHETase consists of a catalytic domain and an extensive lid domain[1]. The catalytic domain adopts the α/β-hydrolase fold typical of a serine hydrolase, with an active site consist the catalytic triad Ser225, Asp492, and His528, which shows significant structural conservation compared to PETase. The lid domain partially covers the active site, hinders its capability to bind with PET fiber, and harbors a well-coordinated calcium cation[1].


Characterization

PET degradation

The degradation of PET polymers using an enzymatic approach requires the synergetic functions of PETase and MHETase, producing terephthalic acids and ethylene glycol by hydrolytic cleavages (Fig.2A). We constructed E. coli expression vectors for the production of PETase and MHETase that can be induced by IPTG (Fig.2B). The production of the proteins was verified by SDS-PAGE analysis (Fig.2C).


Figure 2: Fig.2 FAST-PETase expression (A) Metabolic pathway of PET degradation, PETase catalyzes the cleavage of PET into MHET (mono-2-hydroxyethyl terephthalate) and EG (Ethylene glycol). (B) Genetic circuit constructions of FAST-PETase and FAST-PETase-t with type I dockerin fused to anchor the enzyme subunit onto the cellulosome complex. (C) SDS-page analysis for PETase 5 and PETase 5-t (D) The PH values of different samples of PET degraded by PETases either fused or not fused with type I dockerin domain.


Sequence and Features


Assembly Compatibility:
  • 10
    COMPATIBLE WITH RFC[10]
  • 12
    COMPATIBLE WITH RFC[12]
  • 21
    COMPATIBLE WITH RFC[21]
  • 23
    COMPATIBLE WITH RFC[23]
  • 25
    INCOMPATIBLE WITH RFC[25]
    Illegal NgoMIV site found at 123
    Illegal NgoMIV site found at 237
    Illegal NgoMIV site found at 693
    Illegal AgeI site found at 190
    Illegal AgeI site found at 307
  • 1000
    COMPATIBLE WITH RFC[1000]


References

1. Knott, Brandon C. et al. "Characterization And Engineering Of A Two-Enzyme System For Plastics Depolymerization". Proceedings Of The National Academy Of Sciences, vol 117, no. 41, 2020, pp. 25476-25485. Proceedings Of The National Academy Of Sciences, https://doi.org/10.1073/pnas.2006753117.