1F34

CRYSTAL STRUCTURE OF ASCARIS PEPSIN INHIBITOR-3 BOUND TO PORCINE PEPSIN


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.45 Å
  • R-Value Free: 0.290 
  • R-Value Work: 0.218 
  • R-Value Observed: 0.218 

wwPDB Validation   3D Report Full Report


This is version 1.3 of the entry. See complete history


Literature

Structural basis for the inhibition of porcine pepsin by Ascaris pepsin inhibitor-3.

Ng, K.K.Petersen, J.F.Cherney, M.M.Garen, C.Zalatoris, J.J.Rao-Naik, C.Dunn, B.M.Martzen, M.R.Peanasky, R.J.James, M.N.

(2000) Nat Struct Biol 7: 653-657

  • DOI: https://doi.org/10.1038/77950
  • Primary Citation of Related Structures:  
    1F32, 1F34

  • PubMed Abstract: 

    The three-dimensional structures of pepsin inhibitor-3 (PI-3) from Ascaris suum and of the complex between PI-3 and porcine pepsin at 1. 75 A and 2.45 A resolution, respectively, have revealed the mechanism of aspartic protease inhibition by this unique inhibitor. PI-3 has a new fold consisting of two domains, each comprising an antiparallel beta-sheet flanked by an alpha-helix. In the enzyme-inhibitor complex, the N-terminal beta-strand of PI-3 pairs with one strand of the 'active site flap' (residues 70-82) of pepsin, thus forming an eight-stranded beta-sheet that spans the two proteins. PI-3 has a novel mode of inhibition, using its N-terminal residues to occupy and therefore block the first three binding pockets in pepsin for substrate residues C-terminal to the scissile bond (S1'-S3'). The molecular structure of the pepsin-PI-3 complex suggests new avenues for the rational design of proteinaceous aspartic proteinase inhibitors.


  • Organizational Affiliation

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


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
PEPSIN A326Sus scrofaMutation(s): 1 
EC: 3.4.23.1
UniProt
Find proteins for P00791 (Sus scrofa)
Explore P00791 
Go to UniProtKB:  P00791
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP00791
Sequence Annotations
Expand
  • Reference Sequence
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
MAJOR PEPSIN INHIBITOR PI-3149Ascaris suumMutation(s): 0 
UniProt
Find proteins for P19400 (Ascaris suum)
Explore P19400 
Go to UniProtKB:  P19400
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP19400
Sequence Annotations
Expand
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
MPD
Query on MPD

Download Ideal Coordinates CCD File 
C [auth A](4S)-2-METHYL-2,4-PENTANEDIOL
C6 H14 O2
SVTBMSDMJJWYQN-YFKPBYRVSA-N
Modified Residues  1 Unique
IDChains TypeFormula2D DiagramParent
SEP
Query on SEP
A
L-PEPTIDE LINKINGC3 H8 N O6 PSER
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.45 Å
  • R-Value Free: 0.290 
  • R-Value Work: 0.218 
  • R-Value Observed: 0.218 
  • Space Group: C 2 2 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 65.374α = 90
b = 97.593β = 90
c = 136.394γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
AMoREphasing
CNSrefinement

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2001-02-01
    Type: Initial release
  • Version 1.1: 2008-04-27
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2018-04-04
    Changes: Data collection