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The neutron structure of urate oxidase resolves a long-standing mechanistic conundrum and reveals unexpected changes in protonation.

Oksanen, Esko; Blakeley, Matthew P; El-Hajji, Mohamed; Ryde, Ulf LU and Budayova-Spano, Monika (2014) In PLoS ONE 9(1).
Abstract
Urate oxidase transforms uric acid to 5-hydroxyisourate without the help of cofactors, but the catalytic mechanism has remained enigmatic, as the protonation state of the substrate could not be reliably deduced. We have determined the neutron structure of urate oxidase, providing unique information on the proton positions. A neutron crystal structure inhibited by a chloride anion at 2.3 Å resolution shows that the substrate is in fact 8-hydroxyxanthine, the enol tautomer of urate. We have also determined the neutron structure of the complex with the inhibitor 8-azaxanthine at 1.9 Å resolution, showing the protonation states of the K10-T57-H256 catalytic triad. Together with X-ray data and quantum chemical calculations, these structures... (More)
Urate oxidase transforms uric acid to 5-hydroxyisourate without the help of cofactors, but the catalytic mechanism has remained enigmatic, as the protonation state of the substrate could not be reliably deduced. We have determined the neutron structure of urate oxidase, providing unique information on the proton positions. A neutron crystal structure inhibited by a chloride anion at 2.3 Å resolution shows that the substrate is in fact 8-hydroxyxanthine, the enol tautomer of urate. We have also determined the neutron structure of the complex with the inhibitor 8-azaxanthine at 1.9 Å resolution, showing the protonation states of the K10-T57-H256 catalytic triad. Together with X-ray data and quantum chemical calculations, these structures allow us to identify the site of the initial substrate protonation and elucidate why the enzyme is inhibited by a chloride anion. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
PLoS ONE
volume
9
issue
1
publisher
Public Library of Science
external identifiers
  • pmid:24466188
  • wos:000330288000129
  • scopus:84899805626
ISSN
1932-6203
DOI
10.1371/journal.pone.0086651
language
English
LU publication?
yes
id
811e7984-445f-403e-b67b-9bde82fc3527 (old id 4290593)
date added to LUP
2014-02-27 12:52:24
date last changed
2017-07-30 03:58:34
@article{811e7984-445f-403e-b67b-9bde82fc3527,
  abstract     = {Urate oxidase transforms uric acid to 5-hydroxyisourate without the help of cofactors, but the catalytic mechanism has remained enigmatic, as the protonation state of the substrate could not be reliably deduced. We have determined the neutron structure of urate oxidase, providing unique information on the proton positions. A neutron crystal structure inhibited by a chloride anion at 2.3 Å resolution shows that the substrate is in fact 8-hydroxyxanthine, the enol tautomer of urate. We have also determined the neutron structure of the complex with the inhibitor 8-azaxanthine at 1.9 Å resolution, showing the protonation states of the K10-T57-H256 catalytic triad. Together with X-ray data and quantum chemical calculations, these structures allow us to identify the site of the initial substrate protonation and elucidate why the enzyme is inhibited by a chloride anion.},
  articleno    = {e86651},
  author       = {Oksanen, Esko and Blakeley, Matthew P and El-Hajji, Mohamed and Ryde, Ulf and Budayova-Spano, Monika},
  issn         = {1932-6203},
  language     = {eng},
  number       = {1},
  publisher    = {Public Library of Science},
  series       = {PLoS ONE},
  title        = {The neutron structure of urate oxidase resolves a long-standing mechanistic conundrum and reveals unexpected changes in protonation.},
  url          = {http://dx.doi.org/10.1371/journal.pone.0086651},
  volume       = {9},
  year         = {2014},
}