2QA9

Crystal structure of the second tetrahedral intermediates of SGPB at pH 4.2


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.18 Å
  • R-Value Free: 0.182 
  • R-Value Work: 0.145 

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This is version 1.1 of the entry. See complete history

Literature

1.2A-resolution crystal structures reveal the second tetrahedral intermediates of streptogrisin B (SGPB).

Lee, T.W.James, M.N.

(2008) Biochim.Biophys.Acta 1784: 319-334

  • DOI: 10.1016/j.bbapap.2007.11.012
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Streptogrisin B (SGPB) has served as one of the models for studying the catalytic activities of serine peptidases. Here we report its native crystal structures at pH 4.2 at a resolution of 1.18A, and at pH 7.3 at a resolution of 1.23A. Unexpectedly, ...

    Streptogrisin B (SGPB) has served as one of the models for studying the catalytic activities of serine peptidases. Here we report its native crystal structures at pH 4.2 at a resolution of 1.18A, and at pH 7.3 at a resolution of 1.23A. Unexpectedly, outstanding electron density peaks occurred in the active site and the substrate-binding region of SGPB in the computed maps at both pHs. The densities at pH 4.2 were assigned as a tetrapeptide, Asp-Ala-Ile-Tyr, whereas those at pH 7.3 were assigned as a tyrosine molecule and a leucine molecule existing at equal occupancies in both of the SGPB molecules in the asymmetric unit. Refinement with relaxed geometric restraints resulted in molecular structures representing mixtures of the second tetrahedral intermediates and the enzyme-product complexes of SGPB existing in a pH-dependent equilibrium. Structural comparisons with the complexes of SGPB with turkey ovomucoid third domain (OMTKY3) and its variants have shown that, upon the formation of the tetrahedral intermediate, residues Glu192A to Gly193 of SGPB move towards the alpha-carboxylate O of residue P1 of the bound species, and adjustments in the side-chain conformational angles of His57 and Ser195 of SGPB favor the progression of the catalytic mechanism of SGPB.


    Organizational Affiliation

    Group in Protein Structure and Function, Department of Biochemistry, University of Alberta, Room 4-29, Medical Sciences Building, Edmonton, Alberta T6G 2H7, Canada.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Streptogrisin-B
E
185Streptomyces griseusMutation(s): 0 
Gene Names: sprB
EC: 3.4.21.81
Find proteins for P00777 (Streptomyces griseus)
Go to UniProtKB:  P00777
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
4-mer peptide DAIY
I
4Streptomyces griseusMutation(s): 0 
Gene Names: sprB
EC: 3.4.21.81
Find proteins for P00777 (Streptomyces griseus)
Go to UniProtKB:  P00777
Small Molecules
Ligands 4 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

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Download CCD File 
E
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
CL
Query on CL

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Download CCD File 
E
CHLORIDE ION
Cl
VEXZGXHMUGYJMC-UHFFFAOYSA-M
 Ligand Interaction
GOL
Query on GOL

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Download CCD File 
E
GLYCEROL
GLYCERIN; PROPANE-1,2,3-TRIOL
C3 H8 O3
PEDCQBHIVMGVHV-UHFFFAOYSA-N
 Ligand Interaction
EDO
Query on EDO

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Download CCD File 
E
1,2-ETHANEDIOL
ETHYLENE GLYCOL
C2 H6 O2
LYCAIKOWRPUZTN-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.18 Å
  • R-Value Free: 0.182 
  • R-Value Work: 0.145 
  • Space Group: P 21 21 2
Unit Cell:
Length (Å)Angle (°)
a = 43.461α = 90.00
b = 107.470β = 90.00
c = 36.792γ = 90.00
Software Package:
Software NamePurpose
REFMACrefinement
MOLREPphasing
HKL-2000data scaling
HKL-2000data reduction

Structure Validation

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Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2007-12-11
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Non-polymer description, Version format compliance