7S6Y

Structure of the SARS-CoV-2 main protease in complex with inhibitor MPI32


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.85 Å
  • R-Value Free: 0.258 
  • R-Value Work: 0.229 
  • R-Value Observed: 0.230 

Starting Model: experimental
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Ligand Structure Quality Assessment 


This is version 1.1 of the entry. See complete history


Literature

A systematic exploration of boceprevir-based main protease inhibitors as SARS-CoV-2 antivirals.

Alugubelli, Y.R.Geng, Z.Z.Yang, K.S.Shaabani, N.Khatua, K.Ma, X.R.Vatansever, E.C.Cho, C.C.Ma, Y.Xiao, J.Blankenship, L.R.Yu, G.Sankaran, B.Li, P.Allen, R.Ji, H.Xu, S.Liu, W.R.

(2022) Eur J Med Chem 240: 114596-114596

  • DOI: https://doi.org/10.1016/j.ejmech.2022.114596
  • Primary Citation of Related Structures:  
    7S6W, 7S6X, 7S6Y, 7S6Z, 7S70, 7S71, 7S72, 7S73, 7S74, 7S75

  • PubMed Abstract: 

    Boceprevir is an HCV NSP3 inhibitor that was explored as a repurposed drug for COVID-19. It inhibits the SARS-CoV-2 main protease (M Pro ) and contains an α-ketoamide warhead, a P1 β-cyclobutylalanyl moiety, a P2 dimethylcyclopropylproline, a P3 tert-butylglycine, and a P4 N-terminal tert-butylcarbamide. By introducing modifications at all four positions, we synthesized 20 boceprevir-based M Pro inhibitors including PF-07321332 and characterized their M Pro inhibition potency in test tubes (in vitro) and 293T cells (in cellulo). Crystal structures of M Pro bound with 10 inhibitors and cytotoxicity and antiviral potency of 4 inhibitors were characterized as well. Replacing the P1 site with a β-(S-2-oxopyrrolidin-3-yl)-alanyl (Opal) residue and the warhead with an aldehyde leads to high in vitro potency. The original moieties at P2, P3 and the P4 N-terminal cap positions in boceprevir are better than other tested chemical moieties for high in vitro potency. In crystal structures, all inhibitors form a covalent adduct with the M Pro active site cysteine. The P1 Opal residue, P2 dimethylcyclopropylproline and P4 N-terminal tert-butylcarbamide make strong hydrophobic interactions with M Pro , explaining high in vitro potency of inhibitors that contain these moieties. A unique observation was made with an inhibitor that contains a P4 N-terminal isovaleramide. In its M Pro complex structure, the P4 N-terminal isovaleramide is tucked deep in a small pocket of M Pro that originally recognizes a P4 alanine side chain in a substrate. Although all inhibitors show high in vitro potency, they have drastically different in cellulo potency to inhibit ectopically expressed M Pro in human 293T cells. In general, inhibitors with a P4 N-terminal carbamide or amide have low in cellulo potency. This trend is reversed when the P4 N-terminal cap is changed to a carbamate. The installation of a P3 O-tert-butyl-threonine improves in cellulo potency. Three molecules that contain a P4 N-terminal carbamate were advanced to cytotoxicity tests on 293T cells and antiviral potency tests on three SARS-CoV-2 variants. They all have relatively low cytotoxicity and high antiviral potency with EC 50 values around 1 μM. A control compound with a nitrile warhead and a P4 N-terminal amide has undetectable antiviral potency. Based on all observations, we conclude that a P4 N-terminal carbamate in a boceprevir derivative is key for high antiviral potency against SARS-CoV-2.


  • Organizational Affiliation

    Texas A&M Drug Discovery Laboratory, Department of Chemistry, Texas A&M University, College Station, TX, 77843, USA.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
3C-like proteinase306Severe acute respiratory syndrome coronavirus 2Mutation(s): 0 
Gene Names: rep1a-1b
EC: 3.4.22.69
UniProt
Find proteins for P0DTD1 (Severe acute respiratory syndrome coronavirus 2)
Explore P0DTD1 
Go to UniProtKB:  P0DTD1
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP0DTD1
Sequence Annotations
Expand
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
8GW (Subject of Investigation/LOI)
Query on 8GW

Download Ideal Coordinates CCD File 
B [auth A](1R,2S,5S)-3-[N-(tert-butylcarbamoyl)-3-methyl-L-valyl]-N-{(2S,3R)-4-[(cyclopropylmethyl)amino]-3-hydroxy-4-oxo-1-[(3S)-2-oxopyrrolidin-3-yl]butan-2-yl}-6,6-dimethyl-3-azabicyclo[3.1.0]hexane-2-carboxamide
C31 H52 N6 O6
RTEPKJZIQYUGOI-BLTUZGSGSA-N
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.85 Å
  • R-Value Free: 0.258 
  • R-Value Work: 0.229 
  • R-Value Observed: 0.230 
  • Space Group: I 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 54.313α = 90
b = 81.292β = 97.46
c = 85.628γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
PDB_EXTRACTdata extraction
PROTEUM PLUSdata reduction
Aimlessdata scaling
PHENIXphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Welch FoundationUnited StatesA1715

Revision History  (Full details and data files)

  • Version 1.0: 2022-07-27
    Type: Initial release
  • Version 1.1: 2023-10-18
    Changes: Data collection, Refinement description