3FZN

Intermediate analogue in benzoylformate decarboxylase


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.62 Å
  • R-Value Free: 0.203 
  • R-Value Work: 0.170 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structural and kinetic studies on native intermediates and an intermediate analogue in benzoylformate decarboxylase reveal a least motion mechanism with an unprecedented short-lived predecarboxylation intermediate.

Bruning, M.Berheide, M.Meyer, D.Golbik, R.Bartunik, H.Liese, A.Tittmann, K.

(2009) Biochemistry 48: 3258-3268

  • DOI: 10.1021/bi801957d

  • PubMed Abstract: 
  • The thiamin diphosphate- (ThDP-) dependent enzyme benzoylformate decarboxylase (BFDC) catalyzes the nonoxidative decarboxylation of benzoylformic acid to benzaldehyde and carbon dioxide. To date, no structural information for a cofactor-bound reactio ...

    The thiamin diphosphate- (ThDP-) dependent enzyme benzoylformate decarboxylase (BFDC) catalyzes the nonoxidative decarboxylation of benzoylformic acid to benzaldehyde and carbon dioxide. To date, no structural information for a cofactor-bound reaction intermediate in BFDC is available. For kinetic analysis, a chromophoric substrate analogue was employed that produces various absorbing intermediates during turnover but is a poor substrate with a 10(4)-fold compromised kcat. Here, we have analyzed the steady-state distribution of native intermediates by a combined chemical quench/1H NMR spectroscopic approach and estimated the net rate constants of elementary catalytic steps. At substrate saturation, carbonyl addition of the substrate to the cofactor (k' approximately 500 s-1 at 30 degrees C) and elimination of benzaldehyde (k' approximately 2.400 s-1) were found to be partially rate-determining for catalysis, whereas decarboxylation of the transient 2-mandelyl-ThDP intermediate is 1 order of magnitude faster with k' approximately 16.000 s-1, the largest rate constant of decarboxylation in any thiamin enzyme characterized so far. The X-ray structure of a predecarboxylation intermediate analogue was determined to 1.6 A after cocrystallization of BFDC from Pseudomonas putida with benzoylphosphonic acid methyl ester. In contrast to the free acid, for which irreversible phosphorylation of active center Ser26 was reported, the methyl ester forms a covalent adduct with ThDP with a similar configuration at C2alpha as observed for other thiamin enzymes. The C2-C2alpha bond of the intermediate analogue is out of plane by 7degrees, indicating strain. The phosphonate part of the adduct forms hydrogen bonds with Ser26 and His281, and the 1-OH group is held in place by interactions with His70 and the 4'-amino group of ThDP. The phenyl ring accommodates in a hydrophobic pocket formed by Phe464, Phe397, Leu109, and Leu403. A comparison with the previously determined structure of BFDC in noncovalent complex with the inhibitor (R)-mandelate suggests a least motion mechanism. Binding of benzoylphosphonic acid methyl ester to BFDC was further characterized by CD spectroscopy and stopped-flow kinetics, indicating a two-step binding mechanism with a 200-fold slower carbonyl addition to ThDP than determined for benzoylformic acid, in line with the observed slight structural reorganization of Phe464 due to steric clashes with the phosphonate moiety.


    Organizational Affiliation

    Institute of Technical Biocatalysis, Hamburg UniVersity of Technology, Denickestrasse 15, D-21073 Hamburg, Germany.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Benzoylformate decarboxylase
A, B, C, D
534Pseudomonas putidaMutation(s): 0 
Gene Names: mdlC
EC: 4.1.1.7
Find proteins for P20906 (Pseudomonas putida)
Go to UniProtKB:  P20906
Small Molecules
Ligands 5 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
PO4
Query on PO4

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A, C
PHOSPHATE ION
O4 P
NBIIXXVUZAFLBC-UHFFFAOYSA-K
 Ligand Interaction
D7K
Query on D7K

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A, B, C, D
3-[(4-amino-2-methylpyrimidin-5-yl)methyl]-2-{(S)-hydroxy[(R)-hydroxy(methoxy)phosphoryl]phenylmethyl}-5-(2-{[(R)-hydroxy(phosphonooxy)phosphoryl]oxy}ethyl)-4-methyl-1,3-thiazol-3-ium
C20 H28 N4 O11 P3 S
NEEQBMRCDKRNBV-FQEVSTJZSA-O
 Ligand Interaction
CL
Query on CL

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A, B, C, D
CHLORIDE ION
Cl
VEXZGXHMUGYJMC-UHFFFAOYSA-M
 Ligand Interaction
MG
Query on MG

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A, B, C, D
MAGNESIUM ION
Mg
JLVVSXFLKOJNIY-UHFFFAOYSA-N
 Ligand Interaction
PEG
Query on PEG

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C, D
DI(HYDROXYETHYL)ETHER
C4 H10 O3
MTHSVFCYNBDYFN-UHFFFAOYSA-N
 Ligand Interaction
External Ligand Annotations 
IDBinding Affinity (Sequence Identity %)
D7KKd: 97000 nM PDBBIND
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.62 Å
  • R-Value Free: 0.203 
  • R-Value Work: 0.170 
  • Space Group: P 1
Unit Cell:
Length (Å)Angle (°)
a = 71.510α = 63.46
b = 93.344β = 72.82
c = 94.525γ = 73.21
Software Package:
Software NamePurpose
SCALEPACKdata scaling
MAR345data collection
MOLREPphasing
REFMACrefinement
DENZOdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2009-05-05
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Version format compliance
  • Version 1.2: 2017-11-01
    Type: Advisory, Refinement description