4IMQ

Structural Basis of Substrate Specificity and Protease Inhibition in Norwalk Virus


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.50 Å
  • R-Value Free: 0.185 
  • R-Value Work: 0.170 
  • R-Value Observed: 0.171 

wwPDB Validation   3D Report Full Report


This is version 1.1 of the entry. See complete history


Literature

Structural basis of substrate specificity and protease inhibition in norwalk virus.

Muhaxhiri, Z.Deng, L.Shanker, S.Sankaran, B.Estes, M.K.Palzkill, T.Song, Y.Prasad, B.V.

(2013) J Virol 87: 4281-4292

  • DOI: 10.1128/JVI.02869-12
  • Primary Citation of Related Structures:  
    4IMQ, 4IMZ, 4IN1, 4IN2, 4INH

  • PubMed Abstract: 
  • Norwalk virus (NV), the prototype human calicivirus, is the leading cause of nonbacterial acute gastroenteritis. The NV protease cleaves the polyprotein encoded by open reading frame 1 of the viral genome at five nonhomologous sites, releasing six nonstructural proteins that are essential for viral replication ...

    Norwalk virus (NV), the prototype human calicivirus, is the leading cause of nonbacterial acute gastroenteritis. The NV protease cleaves the polyprotein encoded by open reading frame 1 of the viral genome at five nonhomologous sites, releasing six nonstructural proteins that are essential for viral replication. The structural details of how NV protease recognizes multiple substrates are unclear. In our X-ray structure of an NV protease construct, we observed that the C-terminal tail, representing the native substrate positions P5 to P1, is inserted into the active site cleft of the neighboring protease molecule, providing atomic details of how NV protease recognizes a substrate. The crystallographic structure of NV protease with the C-terminal tail redesigned to mimic P4 to P1 of another substrate site provided further structural details on how the active site accommodates sequence variations in the substrates. Based on these structural analyses, substrate-based aldehyde inhibitors were synthesized and screened for inhibition potency. Crystallographic structures of the protease in complex with each of the three most potent inhibitors were determined. These structures showed concerted conformational changes in the S4 and S2 pockets of the protease to accommodate variations in the P4 and P2 residues of the substrate/inhibitor, which could be a mechanism for how the NV protease recognizes multiple sites in the polyprotein with differential affinities during virus replication. These structures further indicate that the mechanism of inhibition by these inhibitors involves covalent bond formation with the side chain of the conserved cysteine in the active site by nucleophilic addition, and such substrate-based aldehydes could be effective protease inhibitors.


    Organizational Affiliation

    Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, USA.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
3C-like proteaseA183Norovirus Hu/1968/USMutation(s): 0 
Gene Names: ORF1
EC: 3.4.22.66 (PDB Primary Data), 3.6.1.15 (UniProt), 2.7.7.48 (UniProt)
UniProt
Find proteins for Q83883 (Norwalk virus (strain GI/Human/United States/Norwalk/1968))
Explore Q83883 
Go to UniProtKB:  Q83883
Protein Feature View
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  • Reference Sequence
  • Find similar proteins by:  Sequence   |   Structure
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
PEPTIDE INHIBITOR, syc8B4synthetic constructMutation(s): 0 
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SCN
Query on SCN

Download Ideal Coordinates CCD File 
C [auth A], E [auth A]THIOCYANATE ION
C N S
ZMZDMBWJUHKJPS-UHFFFAOYSA-M
 Ligand Interaction
NA
Query on NA

Download Ideal Coordinates CCD File 
D [auth A]SODIUM ION
Na
FKNQFGJONOIPTF-UHFFFAOYSA-N
 Ligand Interaction
Biologically Interesting Molecules (External Reference) 1 Unique
Entity ID: 2
IDChainsNameType/Class2D Diagram3D Interactions
PRD_001062
Query on PRD_001062
Bpeptide inhibitor, syc8Oligopeptide / Inhibitor Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.50 Å
  • R-Value Free: 0.185 
  • R-Value Work: 0.170 
  • R-Value Observed: 0.171 
  • Space Group: P 65 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 122.396α = 90
b = 122.396β = 90
c = 51.354γ = 120
Software Package:
Software NamePurpose
HKL-3000data collection
PHASERphasing
PHENIXrefinement
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2013-02-20
    Type: Initial release
  • Version 1.1: 2013-04-10
    Changes: Database references