1OTV

PqqC, Pyrroloquinolinquinone Synthase C


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.1 Å
  • R-Value Free: 0.230 
  • R-Value Work: 0.195 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Quinone Biogenesis: Structure and Mechanism of PqqC, the Final Catalyst in the Production of Pyrroloquinoline Quinone.

Magnusson, O.T.Toyama, H.Saeki, M.Rojas, A.Reed, J.C.Adachi, O.Liddington, R.C.Klinman, J.P.Schwarzenbacher, R.

(2004) Proc.Natl.Acad.Sci.USA 101: 7913-7918

  • DOI: 10.1073/pnas.0402640101
  • Primary Citation of Related Structures:  1OTW

  • PubMed Abstract: 
  • The biosynthesis of pyrroloquinoline quinone (PQQ), a vitamin and redox cofactor of quinoprotein dehydrogenases, is facilitated by an unknown pathway that requires the expression of six genes, pqqA to -F. PqqC, the protein encoded by pqqC, catalyzes ...

    The biosynthesis of pyrroloquinoline quinone (PQQ), a vitamin and redox cofactor of quinoprotein dehydrogenases, is facilitated by an unknown pathway that requires the expression of six genes, pqqA to -F. PqqC, the protein encoded by pqqC, catalyzes the final step in the pathway in a reaction that involves ring cyclization and eight-electron oxidation of 3a-(2-amino-2-carboxyethyl)-4,5-dioxo-4,5,6,7,8,9-hexahydroquinoline-7,9-dicarboxylic-acid to PQQ. Herein, we describe the crystal structures of PqqC and its complex with PQQ and determine the stoichiometry of H2O2 formation and O2 uptake during the reaction. The PqqC structure(s) reveals a compact seven-helix bundle that provides the scaffold for a positively charged active site cavity. Product binding induces a large conformational change, which results in the active site recruitment of amino acid side chains proposed to play key roles in the catalytic mechanism. PqqC is unusual in that it transfers redox equivalents to molecular oxygen without the assistance of a redox active metal or cofactor. The structure of the enzyme-product complex shows additional electron density next to R179 and C5 of PQQ, which can be modeled as O2 or H2O2, indicating a site for oxygen binding. We propose a reaction sequence that involves base-catalyzed cyclization and a series of quinone-quinol tautomerizations that are followed by cycles of O2/H2O2-mediated oxidations.


    Organizational Affiliation

    Departments of Chemistry and of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Coenzyme PQQ synthesis protein C
A, B
259Klebsiella pneumoniaeGene Names: pqqC
EC: 1.3.3.11
Find proteins for P27505 (Klebsiella pneumoniae)
Go to UniProtKB:  P27505
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.1 Å
  • R-Value Free: 0.230 
  • R-Value Work: 0.195 
  • Space Group: P 21 21 2
Unit Cell:
Length (Å)Angle (°)
a = 74.151α = 90.00
b = 118.127β = 90.00
c = 68.838γ = 90.00
Software Package:
Software NamePurpose
REFMACrefinement
DENZOdata reduction
SCALEPACKdata scaling
SOLVEphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2004-05-11
    Type: Initial release
  • Version 1.1: 2008-04-29
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Advisory, Version format compliance
  • Version 1.3: 2018-01-31
    Type: Advisory, Experimental preparation