9CJN | pdb_00009cjn

Ligase Cp1B


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.70 Å
  • R-Value Free: 
    0.249 (Depositor), 0.248 (DCC) 
  • R-Value Work: 
    0.202 (Depositor), 0.202 (DCC) 
  • R-Value Observed: 
    0.207 (Depositor) 

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

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Ligand Structure Quality Assessment 


This is version 1.1 of the entry. See complete history

Literature

Enzymatic combinatorial synthesis of E-64 and related cysteine protease inhibitors.

Liu, M.Zang, X.Vlahakis, N.W.Rodriguez, J.A.Ohashi, M.Tang, Y.

(2025) Nat Chem Biol 21: 1783-1793

  • DOI: https://doi.org/10.1038/s41589-025-01907-2
  • Primary Citation Related Structures: 
    9CJN, 9CKT, 9CKW, 9CKY, 9CLH, 9EG7

  • PubMed Abstract: 

    E-64 is an irreversible cysteine protease inhibitor prominently used in chemical biology and drug discovery. Here we uncover a nonribosomal peptide synthetase-independent biosynthetic pathway for E-64, which is widely conserved in fungi. The pathway starts with epoxidation of fumaric acid to the warhead (2S,3S)-trans-epoxysuccinic acid with an Fe(II)/α-ketoglutarate-dependent oxygenase, followed by successive condensation with an L-amino acid by an adenosine triphosphate grasp enzyme and with an amine by the fungal example of amide bond synthetase. Both amide bond-forming enzymes display notable biocatalytic potential, including scalability, stereoselectivity toward the warhead and broader substrate scopes in forming the amide bonds. Biocatalytic cascade with these amide bond-forming enzymes generated a library of cysteine protease inhibitors, leading to more potent cathepsin inhibitors. Additionally, one-pot reactions enabled the preparative synthesis of clinically relevant inhibitors. Our work highlights the importance of biosynthetic investigation for enzyme discovery and the potential of amide bond-forming enzymes in synthesizing small-molecule libraries.


  • Organizational Affiliation
    • Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, Los Angeles, CA, USA.

Macromolecule Content 

  • Total Structure Weight: 59.14 kDa 
  • Atom Count: 3,896 
  • Modeled Residue Count: 486 
  • Deposited Residue Count: 517 
  • Unique protein chains: 1

Macromolecules

Find similar proteins by:|  3D Structure
Entity ID: 1
MoleculeChains  Sequence LengthOrganismDetailsImage
Ligase Cp1B517Aspergillus flavusMutation(s): 0 
Gene Names: BDV35DRAFT_157852
UniProt
Find proteins for A0A5N6E3K6 (Aspergillus parasiticus)
Explore A0A5N6E3K6 
Go to UniProtKB:  A0A5N6E3K6
Entity Groups
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupA0A5N6E3K6
Sequence Annotations
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Reference Sequence

Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.70 Å
  • R-Value Free:  0.249 (Depositor), 0.248 (DCC) 
  • R-Value Work:  0.202 (Depositor), 0.202 (DCC) 
  • R-Value Observed: 0.207 (Depositor) 
Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 69.85α = 90
b = 96.23β = 90
c = 129.04γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
XDSdata reduction
XDSdata scaling
PHENIXphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

& Funding Information

Deposition Data

  • Released Date: 2025-05-21 
  • Deposition Author(s): Xin, Z., Yi, T.

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

Revision History  (Full details and data files)

  • Version 1.0: 2025-05-21
    Type: Initial release
  • Version 1.1: 2025-11-12
    Changes: Database references