Crystal structure of SARS-CoV 3C-like protease with B4Z

Experimental Data Snapshot

  • Resolution: 2.20 Å
  • R-Value Free: 0.235 
  • R-Value Work: 0.182 
  • R-Value Observed: 0.185 

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Design, synthesis and crystallographic analysis of nitrile-based broad-spectrum peptidomimetic inhibitors for coronavirus 3C-like proteases

Chuck, C.P.Chen, C.Ke, Z.Wan, D.C.-C.Chow, H.F.Wong, K.B.

(2012) Eur J Med Chem 59C: 1-6

  • DOI: https://doi.org/10.1016/j.ejmech.2012.10.053
  • Primary Citation of Related Structures:  
    3VB3, 3VB4, 3VB5, 3VB6, 3VB7

  • PubMed Abstract: 

    Coronaviral infection is associated with up to 5% of respiratory tract diseases. The 3C-like protease (3CL(pro)) of coronaviruses is required for proteolytic processing of polyproteins and viral replication, and is a promising target for the development of drugs against coronaviral infection. We designed and synthesized four nitrile-based peptidomimetic inhibitors with different N-terminal protective groups and different peptide length, and examined their inhibitory effect on the in-vitro enzymatic activity of 3CL(pro) of severe-acute-respiratory-syndrome-coronavirus. The IC(50) values of the inhibitors were in the range of 4.6-49 μM, demonstrating that the nitrile warhead can effectively inactivate the 3CL(pro) autocleavage process. The best inhibitor, Cbz-AVLQ-CN with an N-terminal carbobenzyloxy group, was ~10x more potent than the other inhibitors tested. Crystal structures of the enzyme-inhibitor complexes showed that the nitrile warhead inhibits 3CL(pro) by forming a covalent bond with the catalytic Cys145 residue, while the AVLQ peptide forms a number of favourable interactions with the S1-S4 substrate-binding pockets. We have further showed that the peptidomimetic inhibitor, Cbz-AVLQ-CN, has broad-spectrum inhibition against 3CL(pro) from human coronavirus strains 229E, NL63, OC43, HKU1, and infectious bronchitis virus, with IC(50) values ranging from 1.3 to 3.7 μM, but no detectable inhibition against caspase-3. In summary, we have shown that the nitrile-based peptidomimetic inhibitors are effective against 3CL(pro), and they inhibit 3CL(pro) from a broad range of coronaviruses. Our results provide further insights into the future design of drugs that could serve as a first line defence against coronaviral infection.

  • Organizational Affiliation

    School of Life Sciences and Center for Protein Science and Crystallography, The Chinese University of Hong Kong, Shatin, Hong Kong.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
3C-like proteinase
A, B
306Severe acute respiratory syndrome-related coronavirusMutation(s): 0 
Gene Names: 1a
EC: 3.4.22
Find proteins for P0C6U8 (Severe acute respiratory syndrome coronavirus)
Explore P0C6U8 
Go to UniProtKB:  P0C6U8
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP0C6U8
Sequence Annotations
  • Reference Sequence

Find similar proteins by:  Sequence   |   3D Structure  

Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
B4Z inhibitorC [auth E],
D [auth F]
5N/AMutation(s): 0 
Sequence Annotations
  • Reference Sequence
Biologically Interesting Molecules (External Reference) 1 Unique
Experimental Data & Validation

Experimental Data

  • Resolution: 2.20 Å
  • R-Value Free: 0.235 
  • R-Value Work: 0.182 
  • R-Value Observed: 0.185 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 52.322α = 90
b = 97.103β = 103.17
c = 67.405γ = 90
Software Package:
Software NamePurpose
CrystalCleardata collection
MOSFLMdata reduction
SCALAdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2012-12-12
    Type: Initial release
  • Version 1.1: 2023-11-08
    Changes: Data collection, Database references, Derived calculations, Refinement description
  • Version 1.2: 2023-12-06
    Changes: Data collection