3GCT

STRUCTURE OF GAMMA-*CHYMOTRYPSIN IN THE RANGE $P*H 2.0 TO $P*H 10.5 SUGGESTS THAT GAMMA-CHYMOTRYPSIN IS A COVALENT ACYL-ENZYME ADDUCT AT LOW $P*H


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.6 Å
  • R-Value Work: 0.173 

wwPDB Validation 3D Report Full Report


This is version 1.5 of the entry. See complete history

Literature

Structure of gamma-chymotrypsin in the range pH 2.0 to pH 10.5 suggests that gamma-chymotrypsin is a covalent acyl-enzyme adduct at low pH.

Dixon, M.M.Brennan, R.G.Matthews, B.W.

(1991) Int.J.Biol.Macromol. 13: 89-96

  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Crystals of gamma-chymotrypsin (gamma-CHT) grown at pH 7.0 are stable from pH 2.0 to 11.0. Crystalline gamma-CHT therefore provides an unusually favourable system to observe the structure of a protein and its bound solvent over a broad range of pH. I ...

    Crystals of gamma-chymotrypsin (gamma-CHT) grown at pH 7.0 are stable from pH 2.0 to 11.0. Crystalline gamma-CHT therefore provides an unusually favourable system to observe the structure of a protein and its bound solvent over a broad range of pH. In this report we describe the high-resolution refined structure of gamma-CHT at pH values of 2.0, 7.0 and 10.5. The apparent tetrapeptide seen bound in the active site of gamma-CHT at pH 7.0 is also present at pH 2.0 and 10.5 although it is better defined at low pH. A comparison of the respective structures shows that there is additional electron density in the low pH structure at the point where the side-chain of Ser 195 approaches most closely to the presumptive inhibitor. This suggests that the adduct is most likely to be covalently linked to the enzyme at low pH and to be non-covalent at higher pH. As the pH is lowered from 7.0 to 2.0, the side-chain of His 40 rotates approximately 120 degrees about its C alpha-C beta bond and, in concert, the side-chain of Gln 34 also rotates approximately 140 degrees about its C alpha-C beta bond. Apart from these localized rearrangements in the vicinity of His 40, the structure of gamma-CHT at pH 2.0 is very similar to that at neutral pH. The structure of gamma-CHT at pH 10.5 is also seen to be almost identical with that at neutral pH. There is no indication that the internal salt bridge between Asp 194 and the alpha-amino group of lle 16 begins to dissociate at pH 10.5. With the exception of the vicinity of His 40, the structure of the bound solvent in the crystal structures at low, neutral and high pH is very similar.(ABSTRACT TRUNCATED AT 250 WORDS)


    Related Citations: 
    • Is Gamma-Chymotrypsin a Tetrapeptide Acyl-Enzyme Adduct of Gamma-Chymotrypsin?
      Dixon, M.M.,Matthews, B.W.
      (1989) Biochemistry 28: 7033


    Organizational Affiliation

    Department of Physics, University of Oregon, Eugene 97403.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
GAMMA-CHYMOTRYPSIN A
E
13Bos taurusMutation(s): 0 
EC: 3.4.21.1
Find proteins for P00766 (Bos taurus)
Go to UniProtKB:  P00766
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
GAMMA-CHYMOTRYPSIN A
F
131Bos taurusMutation(s): 0 
EC: 3.4.21.1
Find proteins for P00766 (Bos taurus)
Go to UniProtKB:  P00766
Entity ID: 3
MoleculeChainsSequence LengthOrganismDetails
GAMMA-CHYMOTRYPSIN A
G
97Bos taurusMutation(s): 0 
EC: 3.4.21.1
Find proteins for P00766 (Bos taurus)
Go to UniProtKB:  P00766
Entity ID: 4
MoleculeChainsSequence LengthOrganismDetails
UNK PRO GLY ALA TYR PEPTIDE
B
5N/AMutation(s): 0 
Protein Feature View is not available: No corresponding UniProt sequence found.
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

Download SDF File 
Download CCD File 
F
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
UNK
Query on UNK
B
L-PEPTIDE LINKINGC4 H9 N O2

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Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.6 Å
  • R-Value Work: 0.173 
  • Space Group: P 42 21 2
Unit Cell:
Length (Å)Angle (°)
a = 70.000α = 90.00
b = 70.000β = 90.00
c = 97.700γ = 90.00
Software Package:
Software NamePurpose
AGROVATA/ROTAVATEdata scaling
TNTrefinement
OSCTSTdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1991-10-15
    Type: Initial release
  • Version 1.1: 2008-03-03
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance
  • Version 1.3: 2011-07-27
    Type: Atomic model, Database references, Derived calculations, Non-polymer description, Structure summary
  • Version 1.4: 2012-12-12
    Type: Other
  • Version 1.5: 2013-03-13
    Type: Other