1EQ9

CRYSTAL STRUCTURE OF FIRE ANT CHYMOTRYPSIN COMPLEXED TO PMSF


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.70 Å
  • R-Value Free: 0.242 
  • R-Value Work: 0.209 
  • R-Value Observed: 0.209 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

The structure of an insect chymotrypsin.

Botos, I.Meyer, E.Nguyen, M.Swanson, S.M.Koomen, J.M.Russell, D.H.Meyer, E.F.

(2000) J Mol Biol 298: 895-901

  • DOI: 10.1006/jmbi.2000.3699
  • Primary Citation of Related Structures:  
    1EQ9

  • PubMed Abstract: 
  • The South American imported fire ant (Solenopsis invicta), without natural enemies in the United States, widely infests the southern United States, causing more than a half billion dollars in health and agriculture-related damage annually in Texas alone. Fire ants are resistant to most insecticides, so control will require a more fundamental understanding of their biochemistry and metabolism leading to the design of selective, ecologically safe insecticides ...

    The South American imported fire ant (Solenopsis invicta), without natural enemies in the United States, widely infests the southern United States, causing more than a half billion dollars in health and agriculture-related damage annually in Texas alone. Fire ants are resistant to most insecticides, so control will require a more fundamental understanding of their biochemistry and metabolism leading to the design of selective, ecologically safe insecticides. The 4th instar larvae play a crucial role in the nutrition of the colony by secreting proteinases (especially chymotrypsin) which digest food products for the entire colony. The first structure of an ant proteolytic enzyme, fire ant chymotrypsin, was determined to atomic resolution (1.7 A). A structural comparison of the ant and mammalian structures confirms the "universality" of the serine proteinase motif and reveals a difference at residues 147-148, which are proteolytically removed in the bovine enzyme but are firmly intact in the ant chymotrypsin, suggesting a different activation mechanism for the latter. Likewise, the absence of the covalently attached propeptide domain (1-15) further suggests an uncharacteristic activation mechanism. The presence of Gly189 in the S1 site is an atypical feature of this chymotrypsin and is comparable only to human leukocyte elastase, hornet chymotrypsin and fiddler crab collagenase. Binding studies confirm the chymotrypsin nature of this novel enzyme.


    Organizational Affiliation

    Department of Biochemistry and Biophysics, Texas A&M University, TX 77843, USA.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
CHYMOTRYPSIN AB222Solenopsis invictaMutation(s): 0 
EC: 3.4.21.1
Find proteins for Q7SIG2 (Solenopsis invicta)
Explore Q7SIG2 
Go to UniProtKB:  Q7SIG2
Protein Feature View
Expand
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
PMS
Query on PMS

Download Ideal Coordinates CCD File 
A, B
phenylmethanesulfonic acid
C7 H8 O3 S
NIXKBAZVOQAHGC-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.70 Å
  • R-Value Free: 0.242 
  • R-Value Work: 0.209 
  • R-Value Observed: 0.209 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 61.12α = 90
b = 85.84β = 90
c = 97.61γ = 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: 2000-10-03
    Type: Initial release
  • Version 1.1: 2008-04-27
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance