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 21WR | pdb_000021wr

X-ray crystal structure of Honey Truffle Sweetener


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.58 Å
  • R-Value Free: 
    0.247 (Depositor), 0.250 (DCC) 
  • R-Value Work: 
    0.196 (Depositor), 0.196 (DCC) 
  • R-Value Observed: 
    0.198 (Depositor) 

Starting Model: in silico
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wwPDB Validation 3D Report Full Report

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This is version 1.1 of the entry. See complete history. 

Literature

Integrated computation-guided thermostabilization of the fungal sweet protein Honey Truffle Sweetener.

Wang, Z., Wang, W., Zhu, F., Zhang, Y., Li, Y., Zhu, Z., Lu, Z., Huang, A., Yu, M., Liu, S.

(2026) Curr Res Food Sci 13: 101584-101584

  • DOI: https://doi.org/10.1016/j.crfs.2026.101584
  • Primary Citation Related Structures: 
    21WR

  • PubMed Abstract: 

    Thermostability limits the use of sweet proteins as sugar substitutes in thermally processed foods. Here, we report an integrated computation-guided workflow for thermostabilizing Honey Truffle Sweetener (HTS), a recently identified fungal sweet protein with low intrinsic stability. We determined the HTS crystal structure and used it to guide subsequent computational analyses. Rosetta and ThermoMPNN evaluated candidate substitutions from complementary physics-based and deep-learning-based perspectives, and the selected single-mutant library was experimentally characterized. The resulting melting-temperature data were then used to develop SMRC-Net, which combines mutation-centered features from the ESM2 protein language model with molecular dynamics-derived structural descriptors to support mutation prioritization. Repeated nested cross-validation supported quantitative T m prediction within the HTS scaffold, while prospective testing showed 9/10 directional agreement in a small, computationally selected variant set. Validated substitutions were then assembled stepwise in small modules, followed by the introduction of an engineered disulfide bond. The final variant, FM, had a melting temperature of 82.1 °C, 27.5 °C higher than that of wild-type HTS. Untreated FM retained sweetness, while separate heat- and pH-treatment assays showed retained solubility and largely preserved secondary-structure profiles. Sweetness after these treatments was not evaluated. Molecular dynamics analyses indicated that FM was not uniformly rigidified but instead exhibited localized flexibility redistribution and a more consolidated conformational ensemble. This work provides a practical computation-guided framework for protein thermostabilization, with potential applicability to other compact proteins.


  • Organizational Affiliation: 
    • State Key Laboratory of Synthetic Biology, Haihe Laboratory of Sustainable Chemical Transformations, Tianjin Key Laboratory of Function and Application of Biological Macromolecular Structures, Faculty of Medicine, School of Life Sciences, Tianjin University, 92 Weijin Road, Nankai District, Tianjin, 300072, China.

Macromolecule Content 

  • Total Structure Weight: 27.35 kDa 
  • Atom Count: 1,992 
  • Modeled Residue Count: 242 
  • Deposited Residue Count: 248 
  • Unique protein chains: 1

Macromolecules

Find similar proteins by:|  3D Structure
Entity ID: 1
MoleculeChains  Sequence LengthOrganismDetailsImage
Honey Truffle Sweetener
A, B
124Mattirolomyces terfezioidesMutation(s): 0 
Entity Groups
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
Sequence Annotations
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Reference Sequence

Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.58 Å
  • R-Value Free:  0.247 (Depositor), 0.250 (DCC) 
  • R-Value Work:  0.196 (Depositor), 0.196 (DCC) 
  • R-Value Observed: 0.198 (Depositor) 
Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 43.81α = 90
b = 38.68β = 95.24
c = 53.11γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
xia2data reduction
Aimlessdata scaling
PHASERphasing

Structure Validation

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Entry History 

& Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Ministry of Science and Technology (MoST, China)China2024YFF1207200
National Natural Science Foundation of China (NSFC)China32000853
Other governmentYESS20200057
Other government24JCQNJC01380

Revision History  (Full details and data files)

  • Version 1.0: 2026-10-07
    Type: Initial release
  • Version 1.1: 2026-10-28
    Changes: Database references