5T7Z

Monoclinic crystal form of the EpoB NRPS cyclization-docking bidomain from Sorangium cellulosum


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.03 Å
  • R-Value Free: 0.212 
  • R-Value Work: 0.180 
  • R-Value Observed: 0.182 

Starting Model: experimental
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wwPDB Validation   3D Report Full Report


This is version 1.5 of the entry. See complete history


Literature

Structural elements of an NRPS cyclization domain and its intermodule docking domain.

Dowling, D.P.Kung, Y.Croft, A.K.Taghizadeh, K.Kelly, W.L.Walsh, C.T.Drennan, C.L.

(2016) Proc Natl Acad Sci U S A 113: 12432-12437

  • DOI: https://doi.org/10.1073/pnas.1608615113
  • Primary Citation of Related Structures:  
    5T7Z, 5T81

  • PubMed Abstract: 

    Epothilones are thiazole-containing natural products with anticancer activity that are biosynthesized by polyketide synthase (PKS)-nonribosomal peptide synthetase (NRPS) enzymes EpoA-F. A cyclization domain of EpoB (Cy) assembles the thiazole functionality from an acetyl group and l-cysteine via condensation, cyclization, and dehydration. The PKS carrier protein of EpoA contributes the acetyl moiety, guided by a docking domain, whereas an NRPS EpoB carrier protein contributes l-cysteine. To visualize the structure of a cyclization domain with an accompanying docking domain, we solved a 2.03-Å resolution structure of this bidomain EpoB unit, comprising residues M1-Q497 (62 kDa) of the 160-kDa EpoB protein. We find that the N-terminal docking domain is connected to the V-shaped Cy domain by a 20-residue linker but otherwise makes no contacts to Cy. Molecular dynamic simulations and additional crystal structures reveal a high degree of flexibility for this docking domain, emphasizing the modular nature of the components of PKS-NRPS hybrid systems. These structures further reveal two 20-Å-long channels that run from distant sites on the Cy domain to the active site at the core of the enzyme, allowing two carrier proteins to dock with Cy and deliver their substrates simultaneously. Through mutagenesis and activity assays, catalytic residues N335 and D449 have been identified. Surprisingly, these residues do not map to the location of the conserved HHxxxDG motif in the structurally homologous NRPS condensation (C) domain. Thus, although both C and Cy domains have the same basic fold, their active sites appear distinct.


  • Organizational Affiliation

    Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139; daniel.dowling@umb.edu cdrennan@mit.edu.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
EpoB541Sorangium cellulosumMutation(s): 1 
Gene Names: epoB
UniProt
Find proteins for Q9KIZ9 (Sorangium cellulosum)
Explore Q9KIZ9 
Go to UniProtKB:  Q9KIZ9
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9KIZ9
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.03 Å
  • R-Value Free: 0.212 
  • R-Value Work: 0.180 
  • R-Value Observed: 0.182 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 49.768α = 90
b = 90.115β = 102.74
c = 63.337γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
HKL-2000data collection
HKL-2000data scaling
PHASERphasing
PDB_EXTRACTdata extraction
HKL-2000data reduction

Structure Validation

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Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Howard Hughes Medical Institute (HHMI)United States--

Revision History  (Full details and data files)

  • Version 1.0: 2016-11-09
    Type: Initial release
  • Version 1.1: 2016-11-16
    Changes: Database references
  • Version 1.2: 2017-09-27
    Changes: Author supporting evidence, Database references, Derived calculations
  • Version 1.3: 2019-11-20
    Changes: Author supporting evidence
  • Version 1.4: 2024-03-06
    Changes: Data collection, Database references
  • Version 1.5: 2024-04-03
    Changes: Refinement description