CD and MCD of CytC3 and taurine dioxygenase

Role of the facial triad in α-KG-dependent oxygenases

Michael L. Neidig, Christina D. Brown, Kenneth M. Light, Danica Galonić Fujimori, Elizabeth M. Nolan, John C. Price, Eric W. Barr, Joseph M. Bollinger, Jr., Carsten Krebs, Christopher T. Walsh, Edward I. Solomon

Research output: Contribution to journalArticle

60 Citations (Scopus)

Abstract

The α-ketoglutarate (α-KG)-dependent oxygenases are a large and diverse class of mononuclear non-heme iron enzymes that require Fe II, α-KG, and dioxygen for catalysis with the α-KG cosubstrate supplying the additional reducing equivalents for oxygen activation. While these systems exhibit a diverse array of reactivities (i.e., hydroxylation, desaturation, ring closure, etc.), they all share a common structural motif at the FeII active site, termed the 2-His-1-carboxylate facial triad. Recently, a new subclass of α-KG-dependent oxygenases has been identified that exhibits novel reactivity, the oxidative halogenation of unactivated carbon centers. These enzymes are also structurally unique in that they do not contain the standard facial triad, as a Cl- ligand is coordinated in place of the carboxylate. An FeII methodology involving CD, MCD, and VTVH MCD spectroscopies was applied to CytC3 to elucidate the active-site structural effects of this perturbation of the coordination sphere. A significant decrease in the affinity of FeII for apo-CytC3 was observed, supporting the necessity of the facial triad for iron coordination to form the resting site. In addition, interesting differences observed in the FeII/α-KG complex relative to the cognate complex in other α-KG-dependent oxygenases indicate the presence of a distorted 6C site with a weak water ligand. Combined with parallel studies of taurine dioxygenase and past studies of clavaminate synthase, these results define a role of the carboxylate ligand of the facial triad in stabilizing water coordination via a H-bonding interaction between the noncoordinating oxygen of the carboxylate and the coordinated water. These studies provide initial insight into the active-site features that favor chlorination by CytC3 over the hydroxylation reactions occurring in related enzymes.

Original languageEnglish (US)
Pages (from-to)14224-14231
Number of pages8
JournalJournal of the American Chemical Society
Volume129
Issue number46
DOIs
StatePublished - Nov 21 2007

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Dioxygenases
Oxygenases
Taurine
Catalytic Domain
Hydroxylation
Enzymes
Halogenation
Ligands
Oxygen
Water
Iron
Chlorination
Catalysis
Spectrum Analysis
Carbon
Chemical activation
Spectroscopy
Hydrogen

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

Cite this

Neidig, M. L., Brown, C. D., Light, K. M., Fujimori, D. G., Nolan, E. M., Price, J. C., ... Solomon, E. I. (2007). CD and MCD of CytC3 and taurine dioxygenase: Role of the facial triad in α-KG-dependent oxygenases. Journal of the American Chemical Society, 129(46), 14224-14231. https://doi.org/10.1021/ja074557r
Neidig, Michael L. ; Brown, Christina D. ; Light, Kenneth M. ; Fujimori, Danica Galonić ; Nolan, Elizabeth M. ; Price, John C. ; Barr, Eric W. ; Bollinger, Jr., Joseph M. ; Krebs, Carsten ; Walsh, Christopher T. ; Solomon, Edward I. / CD and MCD of CytC3 and taurine dioxygenase : Role of the facial triad in α-KG-dependent oxygenases. In: Journal of the American Chemical Society. 2007 ; Vol. 129, No. 46. pp. 14224-14231.
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title = "CD and MCD of CytC3 and taurine dioxygenase: Role of the facial triad in α-KG-dependent oxygenases",
abstract = "The α-ketoglutarate (α-KG)-dependent oxygenases are a large and diverse class of mononuclear non-heme iron enzymes that require Fe II, α-KG, and dioxygen for catalysis with the α-KG cosubstrate supplying the additional reducing equivalents for oxygen activation. While these systems exhibit a diverse array of reactivities (i.e., hydroxylation, desaturation, ring closure, etc.), they all share a common structural motif at the FeII active site, termed the 2-His-1-carboxylate facial triad. Recently, a new subclass of α-KG-dependent oxygenases has been identified that exhibits novel reactivity, the oxidative halogenation of unactivated carbon centers. These enzymes are also structurally unique in that they do not contain the standard facial triad, as a Cl- ligand is coordinated in place of the carboxylate. An FeII methodology involving CD, MCD, and VTVH MCD spectroscopies was applied to CytC3 to elucidate the active-site structural effects of this perturbation of the coordination sphere. A significant decrease in the affinity of FeII for apo-CytC3 was observed, supporting the necessity of the facial triad for iron coordination to form the resting site. In addition, interesting differences observed in the FeII/α-KG complex relative to the cognate complex in other α-KG-dependent oxygenases indicate the presence of a distorted 6C site with a weak water ligand. Combined with parallel studies of taurine dioxygenase and past studies of clavaminate synthase, these results define a role of the carboxylate ligand of the facial triad in stabilizing water coordination via a H-bonding interaction between the noncoordinating oxygen of the carboxylate and the coordinated water. These studies provide initial insight into the active-site features that favor chlorination by CytC3 over the hydroxylation reactions occurring in related enzymes.",
author = "Neidig, {Michael L.} and Brown, {Christina D.} and Light, {Kenneth M.} and Fujimori, {Danica Galonić} and Nolan, {Elizabeth M.} and Price, {John C.} and Barr, {Eric W.} and {Bollinger, Jr.}, {Joseph M.} and Carsten Krebs and Walsh, {Christopher T.} and Solomon, {Edward I.}",
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Neidig, ML, Brown, CD, Light, KM, Fujimori, DG, Nolan, EM, Price, JC, Barr, EW, Bollinger, Jr., JM, Krebs, C, Walsh, CT & Solomon, EI 2007, 'CD and MCD of CytC3 and taurine dioxygenase: Role of the facial triad in α-KG-dependent oxygenases', Journal of the American Chemical Society, vol. 129, no. 46, pp. 14224-14231. https://doi.org/10.1021/ja074557r

CD and MCD of CytC3 and taurine dioxygenase : Role of the facial triad in α-KG-dependent oxygenases. / Neidig, Michael L.; Brown, Christina D.; Light, Kenneth M.; Fujimori, Danica Galonić; Nolan, Elizabeth M.; Price, John C.; Barr, Eric W.; Bollinger, Jr., Joseph M.; Krebs, Carsten; Walsh, Christopher T.; Solomon, Edward I.

In: Journal of the American Chemical Society, Vol. 129, No. 46, 21.11.2007, p. 14224-14231.

Research output: Contribution to journalArticle

TY - JOUR

T1 - CD and MCD of CytC3 and taurine dioxygenase

T2 - Role of the facial triad in α-KG-dependent oxygenases

AU - Neidig, Michael L.

AU - Brown, Christina D.

AU - Light, Kenneth M.

AU - Fujimori, Danica Galonić

AU - Nolan, Elizabeth M.

AU - Price, John C.

AU - Barr, Eric W.

AU - Bollinger, Jr., Joseph M.

AU - Krebs, Carsten

AU - Walsh, Christopher T.

AU - Solomon, Edward I.

PY - 2007/11/21

Y1 - 2007/11/21

N2 - The α-ketoglutarate (α-KG)-dependent oxygenases are a large and diverse class of mononuclear non-heme iron enzymes that require Fe II, α-KG, and dioxygen for catalysis with the α-KG cosubstrate supplying the additional reducing equivalents for oxygen activation. While these systems exhibit a diverse array of reactivities (i.e., hydroxylation, desaturation, ring closure, etc.), they all share a common structural motif at the FeII active site, termed the 2-His-1-carboxylate facial triad. Recently, a new subclass of α-KG-dependent oxygenases has been identified that exhibits novel reactivity, the oxidative halogenation of unactivated carbon centers. These enzymes are also structurally unique in that they do not contain the standard facial triad, as a Cl- ligand is coordinated in place of the carboxylate. An FeII methodology involving CD, MCD, and VTVH MCD spectroscopies was applied to CytC3 to elucidate the active-site structural effects of this perturbation of the coordination sphere. A significant decrease in the affinity of FeII for apo-CytC3 was observed, supporting the necessity of the facial triad for iron coordination to form the resting site. In addition, interesting differences observed in the FeII/α-KG complex relative to the cognate complex in other α-KG-dependent oxygenases indicate the presence of a distorted 6C site with a weak water ligand. Combined with parallel studies of taurine dioxygenase and past studies of clavaminate synthase, these results define a role of the carboxylate ligand of the facial triad in stabilizing water coordination via a H-bonding interaction between the noncoordinating oxygen of the carboxylate and the coordinated water. These studies provide initial insight into the active-site features that favor chlorination by CytC3 over the hydroxylation reactions occurring in related enzymes.

AB - The α-ketoglutarate (α-KG)-dependent oxygenases are a large and diverse class of mononuclear non-heme iron enzymes that require Fe II, α-KG, and dioxygen for catalysis with the α-KG cosubstrate supplying the additional reducing equivalents for oxygen activation. While these systems exhibit a diverse array of reactivities (i.e., hydroxylation, desaturation, ring closure, etc.), they all share a common structural motif at the FeII active site, termed the 2-His-1-carboxylate facial triad. Recently, a new subclass of α-KG-dependent oxygenases has been identified that exhibits novel reactivity, the oxidative halogenation of unactivated carbon centers. These enzymes are also structurally unique in that they do not contain the standard facial triad, as a Cl- ligand is coordinated in place of the carboxylate. An FeII methodology involving CD, MCD, and VTVH MCD spectroscopies was applied to CytC3 to elucidate the active-site structural effects of this perturbation of the coordination sphere. A significant decrease in the affinity of FeII for apo-CytC3 was observed, supporting the necessity of the facial triad for iron coordination to form the resting site. In addition, interesting differences observed in the FeII/α-KG complex relative to the cognate complex in other α-KG-dependent oxygenases indicate the presence of a distorted 6C site with a weak water ligand. Combined with parallel studies of taurine dioxygenase and past studies of clavaminate synthase, these results define a role of the carboxylate ligand of the facial triad in stabilizing water coordination via a H-bonding interaction between the noncoordinating oxygen of the carboxylate and the coordinated water. These studies provide initial insight into the active-site features that favor chlorination by CytC3 over the hydroxylation reactions occurring in related enzymes.

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