1GCD

REFINED CRYSTAL STRUCTURE OF "AGED" AND "NON-AGED" ORGANOPHOSPHORYL CONJUGATES OF GAMMA-CHYMOTRYPSIN


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Refined crystal structures of "aged" and "non-aged" organophosphoryl conjugates of gamma-chymotrypsin.

Harel, M.Su, C.T.Frolow, F.Ashani, Y.Silman, I.Sussman, J.L.

(1991) J.Mol.Biol. 221: 909-918

  • Primary Citation of Related Structures:  1GMH

  • PubMed Abstract: 
  • "Aged" organophosphoryl conjugates of serine hydrolases differ from the corresponding "non-aged" conjugates in their striking resistance to nucleophilic reactivation. The refined X-ray structures of "aged" and "non-aged" organophosphoryl conjugates o ...

    "Aged" organophosphoryl conjugates of serine hydrolases differ from the corresponding "non-aged" conjugates in their striking resistance to nucleophilic reactivation. The refined X-ray structures of "aged" and "non-aged" organophosphoryl conjugates of gamma-chymotrypsin were compared in order to understand the molecular basis for this resistance of "aged" conjugates. "Aged" and "non-aged" crystalline organophosphoryl-gamma-chymotrypsin conjugates were obtained by prolonged soaking of native gamma-chymotrypsin crystals with appropriate organophosphates. Thus, a representative "non-aged" conjugate, diethylphosphoryl-gamma-chymotrypsin, was obtained by soaking native crystals with paraoxon (diethyl-p-nitrophenyl phosphate), and a closely related "aged" conjugate, monoisopropyl-gamma-chymotrypsin, was obtained by soaking with diisopropylphosphorofluoridate. In both crystalline conjugates, the refined structures clearly reveal a high occupancy of the active site by the appropriate organophosphoryl moiety within covalent bonding distance of Ser195 O gamma. Whereas in the "non-aged" conjugate both ethyl groups can be visualized clearly, in the putative "aged" conjugate, as expected, only one isopropyl group is present. There is virtually no difference between the "aged" and "non-aged" conjugates either with respect to the conformation of the polypeptide backbone as a whole or with respect to the positioning of the side-chains within the active site. In the "aged" conjugate, however, close proximity (2.6 A) of the negatively charged phosphate oxygen atom of the dealkylated organophosphoryl group to His57 N epsilon 2 indicates the presence of a salt bridge between these two moieties. In contrast, in the "non-aged" conjugate the DEP moiety retains its two alkyl groups; thus, lacking a negative oxygen atom, it does not enter into such a charge-charge interaction and its nearest oxygen atom is 3.6 A away from His57 N epsilon 2. It is suggested that steric constraints imposed by the salt bridge in the "aged" conjugate lie at the basis of its resistance to reactivation.


    Related Citations: 
    • Gamma-Chymotrypsin is a Complex of Alpha-Chymotrypsin with its Own Autolysis Products
      Harel, M.,Su, C.-T.,Frolow, F.,Silman, I.,Sussman, J.L.
      (1991) Biochemistry 30: 5217


    Organizational Affiliation

    Department of Structural Chemistry, Weizmann Institute of Science, Rehovot, Israel.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
GAMMA-CHYMOTRYPSIN
A
245Bos taurusEC: 3.4.21.1
Find proteins for P00766 (Bos taurus)
Go to UniProtKB:  P00766
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

Download SDF File 
Download CCD File 
A
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
DEP
Query on DEP

Download SDF File 
Download CCD File 
A
DIETHYL PHOSPHONATE
C4 H11 O3 P
MJUJXFBTEFXVKU-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å
  • Space Group: P 42 21 2
Unit Cell:
Length (Å)Angle (°)
a = 69.000α = 90.00
b = 69.000β = 90.00
c = 95.300γ = 90.00
Software Package:
Software NamePurpose
PROLSQrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1994-06-22
    Type: Initial release
  • Version 1.1: 2008-03-03
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance