4HHO

Serum paraoxonase-1 by directed evolution with the H115W mutation


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.1 Å
  • R-Value Free: 0.212 
  • R-Value Work: 0.183 

wwPDB Validation 3D Report Full Report


This is version 1.0 of the entry. See complete history

Literature

Catalytic metal ion rearrangements underline promiscuity and evolvability of a metalloenzyme.

Ben-David, M.Wieczorek, G.Elias, M.Silman, I.Sussman, J.L.Tawfik, D.S.

(2013) J.Mol.Biol. 425: 1028-1038

  • DOI: 10.1016/j.jmb.2013.01.009
  • Primary Citation of Related Structures:  4HHQ

  • PubMed Abstract: 
  • Although largely deemed as structurally conserved, catalytic metal ion sites can rearrange, thereby contributing to enzyme evolvability. Here, we show that in paraoxonase-1, a lipo-lactonase, catalytic promiscuity and divergence into an organophospha ...

    Although largely deemed as structurally conserved, catalytic metal ion sites can rearrange, thereby contributing to enzyme evolvability. Here, we show that in paraoxonase-1, a lipo-lactonase, catalytic promiscuity and divergence into an organophosphate hydrolase are correlated with an alternative mode of the catalytic Ca(2+). We describe the crystal structures of active-site mutants bearing mutations at position 115. The histidine at this position acts as a base to activate the lactone-hydrolyzing water molecule. Mutations to Trp or Gln indeed diminish paraoxonase-1's lactonase activity; however, the promiscuous organophosphate hydrolase activity is enhanced. The structures reveal a 1.8-Å upward displacement towards the enzyme's surface of the catalytic Ca(2+) in the His115 mutants and configurational changes in the ligating side chains and water molecules, relative to the wild-type enzyme. Biochemical analysis and molecular dynamics simulations suggest that this alternative, upward metal mode mediates the promiscuous hydrolysis of organophosphates. The upward Ca(2+) mode observed in the His115 mutants also appears to mediate the wild type's paraoxonase activity. However, whereas the upward mode dominates in the Trp115 mutant, it is scarcely populated in wild type. Thus, the plasticity of active-site metal ions may permit alternative, latent, promiscuous activities and also provide the basis for the divergence of new enzymatic functions.


    Organizational Affiliation

    Department of Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
SERUM PARAOXONASE BY DIRECTED EVOLUTION
A
355N/AN/A
Protein Feature View is not available: No corresponding UniProt sequence found.
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CA
Query on CA

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A
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
 Ligand Interaction
BR
Query on BR

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Download CCD File 
A
BROMIDE ION
Br
CPELXLSAUQHCOX-UHFFFAOYSA-M
 Ligand Interaction
LMT
Query on LMT

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Download CCD File 
A
DODECYL-BETA-D-MALTOSIDE
C24 H46 O11
NLEBIOOXCVAHBD-QKMCSOCLSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.1 Å
  • R-Value Free: 0.212 
  • R-Value Work: 0.183 
  • Space Group: P 43 21 2
Unit Cell:
Length (Å)Angle (°)
a = 93.782α = 90.00
b = 93.782β = 90.00
c = 145.158γ = 90.00
Software Package:
Software NamePurpose
HKL-2000data reduction
HKL-2000data scaling
PHASERphasing
REFMACrefinement
HKL-2000data collection

Structure Validation

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Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2013-03-27
    Type: Initial release