A Mechanistic view of Enzyme Inhibition and Peptide Hydrolysis in the Active Site of the SARS-CoV 3C-Like peptidase

Experimental Data Snapshot

  • Resolution: 1.79 Å
  • R-Value Free: 0.239 
  • R-Value Work: 0.190 
  • R-Value Observed: 0.193 

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A mechanistic view of enzyme inhibition and peptide hydrolysis in the active site of the SARS-CoV 3C-like peptidase

Yin, J.Niu, C.Cherney, M.M.Zhang, J.Huitema, C.Eltis, L.D.Vederas, J.C.James, M.N.

(2007) J Mol Biol 371: 1060-1074

  • DOI: https://doi.org/10.1016/j.jmb.2007.06.001
  • Primary Citation of Related Structures:  
    2Z3C, 2Z3D, 2Z3E

  • PubMed Abstract: 

    The 3C-like main peptidase 3CL(pro) is a viral polyprotein processing enzyme essential for the viability of the Severe Acute Respiratory Syndrome coronavirus (SARS-CoV). While it is generalized that 3CL(pro) and the structurally related 3C(pro) viral peptidases cleave their substrates via a mechanism similar to that underlying the peptide hydrolysis by chymotrypsin-like serine proteinases (CLSPs), some of the hypothesized key intermediates have not been structurally characterized. Here, we present three crystal structures of SARS 3CL(pro) in complex with each of two members of a new class of peptide-based phthalhydrazide inhibitors. Both inhibitors form an unusual thiiranium ring with the nucleophilic sulfur atom of Cys145, trapping the enzyme's catalytic residues in configurations similar to the intermediate states proposed to exist during the hydrolysis of native substrates. Most significantly, our crystallographic data are consistent with a scenario in which a water molecule, possibly via indirect coordination from the carbonyl oxygen of Thr26, has initiated nucleophilic attack on the enzyme-bound inhibitor. Our data suggest that this structure resembles that of the proposed tetrahedral intermediate during the deacylation step of normal peptidyl cleavage.

  • Organizational Affiliation

    Group in Protein Structure and Function, Department of Biochemistry, University of Alberta, Edmonton, AB, Canada T6G 2H7.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Replicase polyprotein 1ab (pp1ab)306Severe acute respiratory syndrome-related coronavirusMutation(s): 0 
Gene Names: rep
EC: 3.4.22
Find proteins for P0C6X7 (Severe acute respiratory syndrome coronavirus)
Explore P0C6X7 
Go to UniProtKB:  P0C6X7
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP0C6X7
Sequence Annotations
  • Reference Sequence

Find similar proteins by:  Sequence   |   3D Structure  

Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
inhibitor5synthetic constructMutation(s): 1 
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on GOL

Download Ideal Coordinates CCD File 
C3 H8 O3
Modified Residues  1 Unique
IDChains TypeFormula2D DiagramParent
Query on Z3E
Experimental Data & Validation

Experimental Data

  • Resolution: 1.79 Å
  • R-Value Free: 0.239 
  • R-Value Work: 0.190 
  • R-Value Observed: 0.193 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 108.565α = 90
b = 81.459β = 104.45
c = 53.359γ = 90
Software Package:
Software NamePurpose
Blu-Icedata collection
HKL-2000data reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

  • Released Date: 2007-07-03 
  • Deposition Author(s): Yin, J.

Revision History  (Full details and data files)

  • Version 1.0: 2007-07-03
    Type: Initial release
  • Version 1.1: 2008-04-23
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Atomic model, Database references, Derived calculations, Non-polymer description, Structure summary, Version format compliance
  • Version 1.3: 2012-12-12
    Changes: Other
  • Version 1.4: 2017-10-11
    Changes: Refinement description
  • Version 1.5: 2019-12-25
    Changes: Advisory, Data collection, Database references, Derived calculations, Source and taxonomy
  • Version 1.6: 2023-11-01
    Changes: Data collection, Database references, Derived calculations, Refinement description
  • Version 1.7: 2023-11-15
    Changes: Data collection, Derived calculations