1W5P

Stepwise introduction of zinc binding site into porphobilinogen synthase of Pseudomonas aeruginosa (mutations A129C, D131C, D139C, P132E)


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.55 Å
  • R-Value Free: 0.185 
  • R-Value Work: 0.157 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Tracking the Evolution of Porphobilinogen Synthase Metal Dependence in Vitro

Frere, F.Reents, H.Schubert, W.-D.Heinz, D.W.Jahn, D.

(2005) J.Mol.Biol. 345: 1059

  • DOI: 10.1016/j.jmb.2004.10.053
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Metal ions are indispensable cofactors for chemical catalysis by a plethora of enzymes. Porphobilinogen synthases (PBGSs), which catalyse the second step of tetrapyrrole biosynthesis, are grouped according to their dependence on Zn(2+). Using site-di ...

    Metal ions are indispensable cofactors for chemical catalysis by a plethora of enzymes. Porphobilinogen synthases (PBGSs), which catalyse the second step of tetrapyrrole biosynthesis, are grouped according to their dependence on Zn(2+). Using site-directed mutagenesis, we embarked on transforming Zn(2+)-independent Pseudomonas aeruginosa PBGS into a Zn(2+)-dependent enzyme. Nine PBGS variants were generated by permutationally introducing three cysteine residues and a further two residues into the active site of the enzyme to match the homologous Zn(2+)-containing PBGS from Escherichia coli. Crystal structures of seven enzyme variants were solved to elucidate the nature of Zn(2+) coordination at high resolution. The three single-cysteine variants were invariably found to be enzymatically inactive and only one (D139C) was found to bind detectable amounts of Zn(2+). The double mutant A129C/D139C is enzymatically active and binds Zn(2+) in a tetrahedral coordination. Structurally and functionally it mimics mycobacterial PBGS, which bears an equivalent Zn(2+)-coordination site. The remaining two double mutants, without known natural equivalents, reveal strongly distorted tetrahedral Zn(2+)-binding sites. Variant A129C/D131C possesses weak PBGS activity while D131C/D139C is inactive. The triple mutant A129C/D131C/D139C, finally, displays an almost ideal tetrahedral Zn(2+)-binding geometry and a significant Zn(2+)-dependent enzymatic activity. Two additional amino acid exchanges further optimize the active site architecture towards the E.coli enzyme with an additional increase in activity. Our study delineates the potential evolutionary path between Zn(2+)-free and Zn(2+)-dependent PBGS enyzmes showing that the rigid backbone of PBGS enzymes is an ideal framework to create or eliminate metal dependence through a limited number of amino acid exchanges.


    Organizational Affiliation

    Institute of Microbiology, Technical University Braunschweig, Spielmannstrasse 7, D-38106 Braunschweig, Germany.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
DELTA-AMINOLEVULINIC ACID DEHYDRATASE
A, B
337Pseudomonas aeruginosa (strain ATCC 15692 / DSM 22644 / CIP 104116 / JCM 14847 / LMG 12228 / 1C / PRS 101 / PAO1)Mutation(s): 4 
Gene Names: hemB
EC: 4.2.1.24
Find proteins for Q59643 (Pseudomonas aeruginosa (strain ATCC 15692 / DSM 22644 / CIP 104116 / JCM 14847 / LMG 12228 / 1C / PRS 101 / PAO1))
Go to UniProtKB:  Q59643
Small Molecules
Ligands 7 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
K
Query on K

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A, B
POTASSIUM ION
K
NPYPAHLBTDXSSS-UHFFFAOYSA-N
 Ligand Interaction
ZN
Query on ZN

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A, B
ZINC ION
Zn
PTFCDOFLOPIGGS-UHFFFAOYSA-N
 Ligand Interaction
SO4
Query on SO4

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A, B
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
FMT
Query on FMT

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A, B
FORMIC ACID
C H2 O2
BDAGIHXWWSANSR-UHFFFAOYSA-N
 Ligand Interaction
GOL
Query on GOL

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A, B
GLYCEROL
GLYCERIN; PROPANE-1,2,3-TRIOL
C3 H8 O3
PEDCQBHIVMGVHV-UHFFFAOYSA-N
 Ligand Interaction
EDO
Query on EDO

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A, B
1,2-ETHANEDIOL
ETHYLENE GLYCOL
C2 H6 O2
LYCAIKOWRPUZTN-UHFFFAOYSA-N
 Ligand Interaction
MG
Query on MG

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A, B
MAGNESIUM ION
Mg
JLVVSXFLKOJNIY-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.55 Å
  • R-Value Free: 0.185 
  • R-Value Work: 0.157 
  • Space Group: P 4 21 2
Unit Cell:
Length (Å)Angle (°)
a = 126.970α = 90.00
b = 126.970β = 90.00
c = 86.432γ = 90.00
Software Package:
Software NamePurpose
REFMACrefinement
SCALEPACKdata scaling
CNSphasing
DENZOdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2005-01-19
    Type: Initial release
  • Version 1.1: 2011-05-08
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance