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Structure of the molybdenum site in YedY, a sulfite oxidase homologue from escherichia coli

Havelius, Kajsa G.V. LU ; Reschke, Stefan ; Horn, Sebastian ; Döring, Alexander ; Niks, Dimitri ; Hille, Russ ; Schulzke, Carola ; Leimkühler, Silke and Haumann, Michael (2011) In Inorganic Chemistry 50(3). p.741-748
Abstract

YedY from Escherichia coli is a new member of the sulfite oxidase family of molybdenum cofactor (Moco)-containing oxidoreductases. We investigated the atomic structure of the molybdenum site in YedY by X-ray absorption spectroscopy, in comparison to human sulfite oxidase (hSO) and to a MoIV model complex. The K-edge energy was indicative of MoV in YedY, in agreement with X-and Q-band electron paramagnetic resonance results, whereas the hSO protein contained MoVI. In YedY and hSO, molybdenum is coordinated by two sulfur ligands from the molybdopterin ligand of the Moco, one thiolate sulfur of a cysteine (average Mo-S bond length of∼2.4 A), and one (axial) oxo ligand (Mo=O,∼1.7 A). hSO contained a second oxo group at Mo as expected, but... (More)

YedY from Escherichia coli is a new member of the sulfite oxidase family of molybdenum cofactor (Moco)-containing oxidoreductases. We investigated the atomic structure of the molybdenum site in YedY by X-ray absorption spectroscopy, in comparison to human sulfite oxidase (hSO) and to a MoIV model complex. The K-edge energy was indicative of MoV in YedY, in agreement with X-and Q-band electron paramagnetic resonance results, whereas the hSO protein contained MoVI. In YedY and hSO, molybdenum is coordinated by two sulfur ligands from the molybdopterin ligand of the Moco, one thiolate sulfur of a cysteine (average Mo-S bond length of∼2.4 A), and one (axial) oxo ligand (Mo=O,∼1.7 A). hSO contained a second oxo group at Mo as expected, but in YedY, two species in about a 1:1 ratio were found at the active site, corresponding to an equatorial Mo-OH bond (∼2.1 A) or possibly to a shorter Mo-O-bond. Yet another oxygen (or nitrogen) at a∼2.6 A distance to Mo in YedY was identified, which could originate from a water molecule in the substrate binding cavity or from an amino acid residue close to the molybdenum site, i.e., Glu104, that is replaced by a glycine in hSO, or Asn45. The addition of the poor substrate dimethyl sulfoxide to YedY left the molybdenum coordination unchanged at high pH. In contrast, we found indications that the better substrate trimethylamine N-oxide and the substrate analogue acetone were bound at a∼2.6 Å distance to the molybdenum, presumably replacing the equatorial oxygen ligand. These findings were used to interpret the recent crystal structure of YedY and bear implications for its catalytic mechanism.

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publishing date
type
Contribution to journal
publication status
published
in
Inorganic Chemistry
volume
50
issue
3
pages
8 pages
publisher
The American Chemical Society (ACS)
external identifiers
  • pmid:21190337
  • scopus:79951627248
ISSN
0020-1669
DOI
10.1021/ic101291j
language
English
LU publication?
no
id
37d7a56b-d49a-471b-a43e-3c92caff1fbd
date added to LUP
2020-01-15 10:23:34
date last changed
2024-01-02 04:05:35
@article{37d7a56b-d49a-471b-a43e-3c92caff1fbd,
  abstract     = {{<p>YedY from Escherichia coli is a new member of the sulfite oxidase family of molybdenum cofactor (Moco)-containing oxidoreductases. We investigated the atomic structure of the molybdenum site in YedY by X-ray absorption spectroscopy, in comparison to human sulfite oxidase (hSO) and to a MoIV model complex. The K-edge energy was indicative of MoV in YedY, in agreement with X-and Q-band electron paramagnetic resonance results, whereas the hSO protein contained MoVI. In YedY and hSO, molybdenum is coordinated by two sulfur ligands from the molybdopterin ligand of the Moco, one thiolate sulfur of a cysteine (average Mo-S bond length of∼2.4 A), and one (axial) oxo ligand (Mo=O,∼1.7 A). hSO contained a second oxo group at Mo as expected, but in YedY, two species in about a 1:1 ratio were found at the active site, corresponding to an equatorial Mo-OH bond (∼2.1 A) or possibly to a shorter Mo-O-bond. Yet another oxygen (or nitrogen) at a∼2.6 A distance to Mo in YedY was identified, which could originate from a water molecule in the substrate binding cavity or from an amino acid residue close to the molybdenum site, i.e., Glu104, that is replaced by a glycine in hSO, or Asn45. The addition of the poor substrate dimethyl sulfoxide to YedY left the molybdenum coordination unchanged at high pH. In contrast, we found indications that the better substrate trimethylamine N-oxide and the substrate analogue acetone were bound at a∼2.6 Å distance to the molybdenum, presumably replacing the equatorial oxygen ligand. These findings were used to interpret the recent crystal structure of YedY and bear implications for its catalytic mechanism.</p>}},
  author       = {{Havelius, Kajsa G.V. and Reschke, Stefan and Horn, Sebastian and Döring, Alexander and Niks, Dimitri and Hille, Russ and Schulzke, Carola and Leimkühler, Silke and Haumann, Michael}},
  issn         = {{0020-1669}},
  language     = {{eng}},
  month        = {{02}},
  number       = {{3}},
  pages        = {{741--748}},
  publisher    = {{The American Chemical Society (ACS)}},
  series       = {{Inorganic Chemistry}},
  title        = {{Structure of the molybdenum site in YedY, a sulfite oxidase homologue from escherichia coli}},
  url          = {{http://dx.doi.org/10.1021/ic101291j}},
  doi          = {{10.1021/ic101291j}},
  volume       = {{50}},
  year         = {{2011}},
}