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Title: Structural and Mechanistic Studies on Klebsiella pneumoniae 2-Oxo-4-hydroxy-4-carboxy-5-ureidoimidazoline Decarboxylase

Abstract

The stereospecific oxidative degradation of uric acid to (S)-allantoin was recently shown to proceed via three enzymatic steps. The final conversion is a decarboxylation of the unstable intermediate 2-oxo-4-hydroxy-4-carboxy-5-ureidoimidazoline (OHCU) and is catalyzed by OHCU decarboxylase. Here we present the structures of Klebsiella pneumoniae OHCU decarboxylase in unliganded form and with bound allantoin. These structures provide evidence that ligand binding organizes the active site residues for catalysis. Modeling of the substrate and intermediates provides additional support for this hypothesis. In addition we characterize the steady state kinetics of this enzyme and report the first OHCU decarboxylase inhibitor, allopurinol, a structural isomer of hypoxanthine. This molecule is a competitive inhibitor of K. pneumoniae OHCU decarboxylase with a K{sub i} of 30 {+-} 2 {micro}m. Circular dichroism measurements confirm structural observations that this inhibitor disrupts the necessary organization of the active site. Our structural and biochemical studies also provide further insights into the mechanism of catalysis of OHCU decarboxylation.

Authors:
;  [1]
  1. Cornell
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
USDOE
OSTI Identifier:
1002852
Resource Type:
Journal Article
Journal Name:
J. Biol. Chem.
Additional Journal Information:
Journal Volume: 285; Journal Issue: (46) ; 11, 2010; Journal ID: ISSN 0021-9258
Country of Publication:
United States
Language:
ENGLISH
Subject:
59 BASIC BIOLOGICAL SCIENCES; 99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE; ALLANTOIN; CATALYSIS; DECARBOXYLASES; DECARBOXYLATION; DICHROISM; ENZYMES; HYPOTHESIS; HYPOXANTHINE; ISOMERS; KINETICS; KLEBSIELLA; RESIDUES; SIMULATION; SUBSTRATES; URIC ACID

Citation Formats

French, Jarrod B, and Ealick, Steven E. Structural and Mechanistic Studies on Klebsiella pneumoniae 2-Oxo-4-hydroxy-4-carboxy-5-ureidoimidazoline Decarboxylase. United States: N. p., 2010. Web. doi:10.1074/jbc.M110.156034.
French, Jarrod B, & Ealick, Steven E. Structural and Mechanistic Studies on Klebsiella pneumoniae 2-Oxo-4-hydroxy-4-carboxy-5-ureidoimidazoline Decarboxylase. United States. https://doi.org/10.1074/jbc.M110.156034
French, Jarrod B, and Ealick, Steven E. 2010. "Structural and Mechanistic Studies on Klebsiella pneumoniae 2-Oxo-4-hydroxy-4-carboxy-5-ureidoimidazoline Decarboxylase". United States. https://doi.org/10.1074/jbc.M110.156034.
@article{osti_1002852,
title = {Structural and Mechanistic Studies on Klebsiella pneumoniae 2-Oxo-4-hydroxy-4-carboxy-5-ureidoimidazoline Decarboxylase},
author = {French, Jarrod B and Ealick, Steven E},
abstractNote = {The stereospecific oxidative degradation of uric acid to (S)-allantoin was recently shown to proceed via three enzymatic steps. The final conversion is a decarboxylation of the unstable intermediate 2-oxo-4-hydroxy-4-carboxy-5-ureidoimidazoline (OHCU) and is catalyzed by OHCU decarboxylase. Here we present the structures of Klebsiella pneumoniae OHCU decarboxylase in unliganded form and with bound allantoin. These structures provide evidence that ligand binding organizes the active site residues for catalysis. Modeling of the substrate and intermediates provides additional support for this hypothesis. In addition we characterize the steady state kinetics of this enzyme and report the first OHCU decarboxylase inhibitor, allopurinol, a structural isomer of hypoxanthine. This molecule is a competitive inhibitor of K. pneumoniae OHCU decarboxylase with a K{sub i} of 30 {+-} 2 {micro}m. Circular dichroism measurements confirm structural observations that this inhibitor disrupts the necessary organization of the active site. Our structural and biochemical studies also provide further insights into the mechanism of catalysis of OHCU decarboxylation.},
doi = {10.1074/jbc.M110.156034},
url = {https://www.osti.gov/biblio/1002852}, journal = {J. Biol. Chem.},
issn = {0021-9258},
number = (46) ; 11, 2010,
volume = 285,
place = {United States},
year = {Fri Nov 12 00:00:00 EST 2010},
month = {Fri Nov 12 00:00:00 EST 2010}
}