The 2-His-1-carboxylate facial triad: a versatile platform for dioxygen activation by mononuclear non-heme iron(II) enzymes

  • Kevin D. Koehntop
  • Joseph P. Emerson
  • Lawrence QueJr
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DOI: 10.1007/s00775-005-0624-x

Cite this article as:
Koehntop, K.D., Emerson, J.P. & Que, L. J Biol Inorg Chem (2005) 10: 87. doi:10.1007/s00775-005-0624-x

Abstract

General knowledge of dioxygen-activating mononuclear non-heme iron(II) enzymes containing a 2-His-1-carboxylate facial triad has significantly expanded in the last few years, due in large part to the extensive library of crystal structures that is now available. The common structural motif utilized by this enzyme superfamily acts as a platform upon which a wide assortment of substrate transformations are catalyzed. The facial triad binds a divalent metal ion at the active site, which leaves the opposite face of the octahedron available to coordinate a variety of exogenous ligands. The binding of substrate activates the metal center for attack by dioxygen, which is subsequently converted to a high-valent iron intermediate, a formidable oxidizing species. Herein, we summarize crystallographic and mechanistic features of this metalloenzyme superfamily, which has enabled the proposal of a common but flexible pathway for dioxygen activation.

Keywords

α-Ketoglutarate dependent enzymes 2-His-1-carboxylate facial triad Extradiol-cleaving catechol dioxygenases Pterin-dependent hydroxylases Rieske dioxygenases 

Abbreviations

α-KG

α-Ketoglutarate

2,3-CTD

Catechol 2,3-dioxygenase

4,5-PCD

Protocatechuate 4,5-dioxygenase

A1

Deoxyguanidinoproclavaminate

ACCO

1-Aminocyclopropane-1-carboxylic acid oxidase

ACV

δ-(L-α-Aminoadipoyl)-L-cysteinyl-D-valine

ANS

Anthocyanidin synthase

AtsK

Alkylsulfatase

BH4

6(R)-L-erythro-5,6,7,8-Tetrahydrobiopterin

BphC

2,3-Dihydroxybiphenyl 1,2-dioxygenase

CarC

Carbapenem synthase

CAS

Clavaminate synthase

DAOCS

Deacetoxycephalosporin C synthase

DFT

Density functional theory

DHBD

Synonymous with BphC

DHBP

2,3-Dihydroxybiphenyl

EXAFS

Extended X-ray absorption fine structure

FIH-1

Factor-inhibiting hypoxia-inducible factor-1

HGO

Homogentisate 1,2-dioxygenase

HPCD

Homoprotocatechuate 2,3-dioxygenase

HPPD

4-Hydroxyphenylpyruvate dioxygenase

IPNS

Isopenicillin N synthase

LigAB

Synonymous with 4,5-PCD

MCD

Magnetic circular dichroism

MndD

MnII-dependent HPCD

MPC

Metapyrocatechase (synonymous with 2,3-CTD)

NDO

Naphthalene 1,2-dioxygenase

PCV

Proclavaminate

PheOH

Phenylalanine hydroxylase

TauD

Taurine/α-KG dioxygenase

THA

3-(2-Thienyl)-L-alanine

TrpOH

Tryptophan hydroxylase

TyrOH

Tyrosine hydroxylase

Copyright information

© SBIC 2005

Authors and Affiliations

  • Kevin D. Koehntop
    • 1
  • Joseph P. Emerson
    • 1
  • Lawrence QueJr
    • 1
  1. 1.Department of Chemistry and Center for Metals in BiocatalysisUniversity of MinnesotaMinneapolisUSA