Acetolactate Synthase from Trichoderma harzianum

Experimental Data Snapshot

  • Resolution: 2.28 Å
  • R-Value Free: 0.230 
  • R-Value Work: 0.196 
  • R-Value Observed: 0.198 

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Harzianic Acid from Trichoderma afroharzianum Is a Natural Product Inhibitor of Acetohydroxyacid Synthase.

Xie, L.Zang, X.Cheng, W.Zhang, Z.Zhou, J.Chen, M.Tang, Y.

(2021) J Am Chem Soc 

  • DOI: https://doi.org/10.1021/jacs.1c03988
  • Primary Citation of Related Structures:  
    7EGV, 7EHE

  • PubMed Abstract: 

    Acetohydroxyacid synthase (AHAS) is the first enzyme in the branched-chain amino acid biosynthetic pathway and is a validated target for herbicide and fungicide development. Here we report harzianic acid (HA, 1 ) produced by the biocontrol fungus Trichoderma afroharzianum t-22 (Tht22) as a natural product inhibitor of AHAS. The biosynthetic pathway of HA was elucidated with heterologous reconstitution. Guided by a putative self-resistance enzyme in the genome, HA was biochemically demonstrated to be a selective inhibitor of fungal AHAS, including those from phytopathogenic fungi. In addition, HA can inhibit a common resistant variant of AHAS in which the active site proline is mutated. Structural analysis of AHAS complexed with HA revealed the molecular basis of competitive inhibition, which differs from all known commercial AHAS inhibitors. The alternative binding mode also rationalizes the selectivity of HA, as well as effectiveness toward resistant mutants. A proposed role of HA biosynthesis by Tht22 in the rhizosphere is discussed based on the data.

  • Organizational Affiliation

    Biotechnology Research Institute, The Chinese Academy of Agricultural Sciences, 12 Zhongguancun South Street, Beijing 100081, P. R. China.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Acetolactate synthase
A, B
688Trichoderma harzianumMutation(s): 3 
Gene Names: CI102_2746
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.28 Å
  • R-Value Free: 0.230 
  • R-Value Work: 0.196 
  • R-Value Observed: 0.198 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 79.1α = 90
b = 88.53β = 90
c = 188.13γ = 90
Software Package:
Software NamePurpose
XDSdata reduction
XDSdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2021-06-30
    Type: Initial release
  • Version 1.1: 2023-11-29
    Changes: Data collection, Database references, Refinement description