Crystal structure of TnmH

Experimental Data Snapshot

  • Resolution: 2.74 Å
  • R-Value Free: 0.254 
  • R-Value Work: 0.202 
  • R-Value Observed: 0.205 

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This is version 1.3 of the entry. See complete history


Characterization of TnmH as anO-Methyltransferase Revealing Insights into Tiancimycin Biosynthesis and Enabling a Biocatalytic Strategy To Prepare Antibody-Tiancimycin Conjugates.

Adhikari, A.Teijaro, C.N.Yan, X.Chang, C.Y.Gui, C.Liu, Y.C.Crnovcic, I.Yang, D.Annaval, T.Rader, C.Shen, B.

(2020) J Med Chem 63: 8432-8441

  • DOI: https://doi.org/10.1021/acs.jmedchem.0c00799
  • Primary Citation of Related Structures:  
    6CLW, 6CLX

  • PubMed Abstract: 

    The enediynes are among the most cytotoxic molecules known, and their use as anticancer drugs has been successfully demonstrated by targeted delivery. Clinical advancement of the anthraquinone-fused enediynes has been hindered by their low titers and lack of functional groups to enable the preparation of antibody-drug conjugates (ADCs). Here we report biochemical and structural characterization of TnmH from the tiancimycin (TNM) biosynthetic pathway, revealing that (i) TnmH catalyzes regiospecific methylation at the C-7 hydroxyl group, (ii) TnmH exhibits broad substrate promiscuity toward hydroxyanthraquinones and S-alkylated SAM analogues and catalyzes efficient installation of reactive alkyl handles, (iii) the X-ray crystal structure of TnmH provides the molecular basis to account for its broad substrate promiscuity, and (iv) TnmH as a biocatalyst enables the development of novel conjugation strategies to prepare antibody-TNM conjugates. These findings should greatly facilitate the construction and evaluation of antibody-TNM conjugates as next-generation ADCs for targeted chemotherapy.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B
364Streptomyces sp. CB03234Mutation(s): 0 
Gene Names: tnmHAMK26_31990
Find proteins for A0A125SA05 (Streptomyces sp. (strain CB03234))
Explore A0A125SA05 
Go to UniProtKB:  A0A125SA05
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupA0A125SA05
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.74 Å
  • R-Value Free: 0.254 
  • R-Value Work: 0.202 
  • R-Value Observed: 0.205 
  • Space Group: P 31 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 110.86α = 90
b = 110.86β = 90
c = 113.31γ = 120
Software Package:
Software NamePurpose
MOSFLMdata reduction
SCALAdata scaling

Structure Validation

View Full Validation Report

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2019-03-06
    Type: Initial release
  • Version 1.1: 2019-12-04
    Changes: Author supporting evidence
  • Version 1.2: 2020-09-16
    Changes: Database references
  • Version 1.3: 2023-10-04
    Changes: Data collection, Database references, Refinement description