1QIX

Porcine pancreatic elastase complexed with human beta-casomorphin-7


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.90 Å
  • R-Value Free: 0.219 
  • R-Value Work: 0.172 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Structure of a Specific Acyl-Enzyme Complex Formed between Beta-Casomorphin-7 and Porcine Pancreatic Elastase

Wilmouth, R.C.Clifton, I.J.Robinson, C.V.Roach, P.L.Aplin, R.T.Westwood, N.J.Hajdu, J.Schofield, C.J.

(1997) Nat Struct Biol 4: 456

  • DOI: 10.1038/nsb0697-456
  • Primary Citation of Related Structures:  
    1QIX

  • PubMed Abstract: 
  • Mass spectrometric screening reveals that an unmodified natural heptapeptide--human beta-casomorphin-7, an internal sequence of human beta-casein that possesses opioid-like activity--reacts with porcine pancreatic elastase to form an unusually stable ...

    Mass spectrometric screening reveals that an unmodified natural heptapeptide--human beta-casomorphin-7, an internal sequence of human beta-casein that possesses opioid-like activity--reacts with porcine pancreatic elastase to form an unusually stable acyl-enzyme complex at low pH. X-ray crystallographic analysis (to 1.9 A resolution) at pH 5 shows continuous electron density linking the C-terminal isoleucine of beta-casomorphin-7 to Ser 195 through an ester bond. The structure reveals a well defined water molecule (Wat 317), equidistant between the carbon of the ester carbonyl and N epsilon 2 of His 57. Deprotonation of Wat 317 will produce a hydroxide ion positioned to attack the ester carbonyl through the favoured Bürgi-Dunitz trajectory.


    Related Citations: 
    • Structure of Native Porcine Pancreatic Elastase at 1.65A Resolution
      Meyer, E., Cole, G., Radhakrishnan, R., Epp, O.
      (1988) Acta Crystallogr B 44: 26
    • Human Beta-Casein
      Greenberg, R., Groves, M.L., Dower, H.J.
      (1984) J Biol Chem 259: 5132

    Organizational Affiliation

    Oxford Centre for Molecular Sciences, UK.



Macromolecules
  • Find similar proteins by:  Sequence   |   Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
BETA-CASOMORPHIN-7A7Homo sapiensMutation(s): 0 
Protein Feature View
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  • Reference Sequence
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
ELASTASEB240Sus scrofaMutation(s): 0 
Gene Names: CELA1ELA1
EC: 3.4.21.11 (PDB Primary Data), 3.4.21.36 (UniProt)
Find proteins for P00772 (Sus scrofa)
Explore P00772 
Go to UniProtKB:  P00772
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

Download CCD File 
B
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
CA
Query on CA

Download CCD File 
B
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.90 Å
  • R-Value Free: 0.219 
  • R-Value Work: 0.172 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 51.282α = 90
b = 58.24β = 90
c = 75.437γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
MOSFLMdata reduction
SCALAdata scaling

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1999-12-14
    Type: Initial release
  • Version 1.1: 2011-05-08
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance