skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Evaluation of a concerted vs. sequential oxygen activation mechanism in α-ketoglutarate–dependent nonheme ferrous enzymes

Journal Article · · Proceedings of the National Academy of Sciences of the United States of America
 [1];  [1];  [1]; ORCiD logo [2]; ORCiD logo [3];  [3];  [4];  [2]; ORCiD logo [2]
  1. Stanford Univ., CA (United States)
  2. Stanford Univ., CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States). Stanford Synchrotron Radiation Lightsource (SSRL)
  3. Technical Univ. of Denmark, Lyngby (Denmark)
  4. SLAC National Accelerator Lab., Menlo Park, CA (United States). Stanford Synchrotron Radiation Lightsource (SSRL)

Determining the requirements for efficient oxygen (O2) activation is key to understanding how enzymes maintain efficacy and mitigate unproductive, often detrimental reactivity. For the α-ketoglutarate (αKG)–dependent nonheme iron enzymes, both a concerted mechanism (both cofactor and substrate binding prior to reaction with O2) and a sequential mechanism (cofactor binding and reaction with O2precede substrate binding) have been proposed. Deacetoxycephalosporin C synthase (DAOCS) is an αKG-dependent nonheme iron enzyme for which both of these mechanisms have been invoked to generate an intermediate that catalyzes oxidative ring expansion of penicillin substrates in cephalosporin biosynthesis. Interestingly, spectroscopy shows that, in contrast to other αKG-dependent enzymes (which are six coordinate when only αKG is bound to the FeII), αKG binding to FeII-DAOCS results in ~45% five-coordinate sites that selectively react with O2relative to the remaining six-coordinate sites. However, this reaction produces an FeIIIspecies that does not catalyze productive ring expansion. Alternatively, simultaneous αKG and substrate binding to FeII-DAOCS produces five-coordinate sites that rapidly react with O2to form an FeIV=O intermediate that then reacts with substrate to produce cephalosporin product. These results demonstrate that the concerted mechanism is operative in DAOCS and by extension, other nonheme iron enzymes.

Research Organization:
SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
Sponsoring Organization:
National Institutes of Health (NIH); USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE Office of Science (SC), Biological and Environmental Research (BER); National Institute of General Medical Sciences (NIGMS); Independent Research Fund Denmark
Grant/Contract Number:
AC02-76SF00515; GM 40392; P41GM103393; DFF-6108-00247
OSTI ID:
1608322
Journal Information:
Proceedings of the National Academy of Sciences of the United States of America, Vol. 117, Issue 10; ISSN 0027-8424
Publisher:
National Academy of SciencesCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 12 works
Citation information provided by
Web of Science

References (51)

Two Distinct Mechanisms for C–C Desaturation by Iron(II)- and 2-(Oxo)glutarate-Dependent Oxygenases: Importance of α-Heteroatom Assistance journal April 2018
Cephalosporin biosynthesis: A branched pathway sensitive to an isotope effect journal December 1991
Structural insight into antibiotic fosfomycin biosynthesis by a mononuclear iron enzyme journal July 2005
The roles of clavaminic acid and proclavaminic acid in clavulanic acid biosynthesis journal January 1987
Tetrahydropterin-Dependent Amino Acid Hydroxylases journal June 1999
Insight into the mechanism of an iron dioxygenase by resolution of steps following the FeIVboxHO species journal February 2010
Circular Dichroism and Magnetic Circular Dichroism Spectroscopic Studies of the Non-Heme Ferrous Active Site in Clavaminate Synthase and Its Interaction with α-Ketoglutarate Cosubstrate journal February 1998
Magnetic Circular Dichroism Spectroscopic Studies of Mononuclear Non-Heme Ferrous Model Complexes. Correlation of Excited- and Ground-State Electronic Structure with Geometry journal April 1998
Evidence for Modulation of Oxygen Rebound Rate in Control of Outcome by Iron(II)- and 2-Oxoglutarate-Dependent Oxygenases journal September 2019
Substrate Binding to the α-Ketoglutarate-Dependent Non-Heme Iron Enzyme Clavaminate Synthase 2:  Coupling Mechanism of Oxidative Decarboxylation and Hydroxylation journal December 1998
Kinetic and crystallographic studies on deacetoxycephalosporin C synthase (DAOCS) journal May 2001
The biosynthesis of penicillins and cephalosporins journal January 1988
Catalytic Mechanisms of Fe(II)- and 2-Oxoglutarate-dependent Oxygenases journal July 2015
The structural basis of cephalosporin formation in a mononuclear ferrous enzyme
  • Valegård, Karin; van Scheltinga, Anke C. Terwisscha; Dubus, Alain
  • Nature Structural & Molecular Biology, Vol. 11, Issue 1 https://doi.org/10.1038/nsmb712
journal December 2003
α-Amine Desaturation of d -Arginine by the Iron(II)- and 2-(Oxo)glutarate-Dependent l -Arginine 3-Hydroxylase, VioC journal October 2018
Oxidative dealkylation DNA repair mediated by the mononuclear non-heme iron AlkB proteins journal April 2006
Structure of a cephalosporin synthase journal August 1998
Characterization of Extradiol Dioxygenases from a Polychlorinated Biphenyl-Degrading Strain That Possess Higher Specificities for Chlorinated Metabolites journal February 2003
Aberrant activity of the DNA repair enzyme AlkB journal May 2004
O 2 Activation by Nonheme Fe II α-Ketoglutarate-Dependent Enzyme Variants: Elucidating the Role of the Facial Triad Carboxylate in FIH journal August 2018
Spectroscopy and Kinetics of Wild-Type and Mutant Tyrosine Hydroxylase: Mechanistic Insight into O 2 Activation journal June 2009
Autocatalysed oxidative modifications to 2-oxoglutarate dependent oxygenases: Oxidative modifications to 2OG oxygenases journal February 2012
Spectroscopic and Electronic Structure Studies of 2,3-Dihydroxybiphenyl 1,2-Dioxygenase:  O 2 Reactivity of the Non-Heme Ferrous Site in Extradiol Dioxygenases journal September 2003
CD and MCD of CytC3 and Taurine Dioxygenase:  Role of the Facial Triad in α-KG-Dependent Oxygenases journal October 2007
Kinetic Dissection of the Catalytic Mechanism of Taurine:α-Ketoglutarate Dioxygenase (TauD) from Escherichia coli journal June 2005
Utilization of Hydrogen Bonds To Stabilize M−O(H) Units:  Synthesis and Properties of Monomeric Iron and Manganese Complexes with Terminal Oxo and Hydroxo Ligands journal February 2004
Copurification and characterization of deacetoxycephalosporin C synthetase/hydroxylase from Cephalosporium acremonium. journal January 1987
Characterization of Terminal Iron(III)–Oxo and Iron(III)–Hydroxo Complexes Derived from O 2 Activation journal November 2019
Orthric Rieske dioxygenases for degrading mixtures of 2,4-dinitrotoluene/naphthalene and 2-amino-4,6-dinitrotoluene/4-amino-2,6-dinitrotoluene journal December 2006
Spectroscopic Studies of the Mononuclear Non-Heme Fe II Enzyme FIH: Second-Sphere Contributions to Reactivity journal June 2013
The First Direct Characterization of a High-Valent Iron Intermediate in the Reaction of an α-Ketoglutarate-Dependent Dioxygenase:  A High-Spin Fe(IV) Complex in Taurine/α-Ketoglutarate Dioxygenase (TauD) from Escherichia coli journal June 2003
Geometric and Electronic Structure/Function Correlations in Non-Heme Iron Enzymes journal January 2000
Variable-temperature variable-field magnetic circular dichroism studies of the iron(II) active site in metapyrocatechase: implications for the molecular mechanism of extradiol dioxygenases journal May 1991
Studies on the active site of deacetoxycephalosporin C synthase journal April 1999
Spectroscopic Studies of Substrate Interactions with Clavaminate Synthase 2, a Multifunctional α-KG-Dependent Non-Heme Iron Enzyme:  Correlation with Mechanisms and Reactivities journal July 2001
Geometric and Electronic Structure Contributions to Function in Non-heme Iron Enzymes journal July 2013
Stereochemical fate of chiral methyl of valine in the ring expansion of penicillin N to deacetoxycephalosporin C journal August 1985
Measurement of g Values in the Electron Spin Resonance Spectra of Free Radicals journal December 1965
Studies on Deacetoxycephalosporin C Synthase Support a Consensus Mechanism for 2-Oxoglutarate Dependent Oxygenases journal April 2014
Spectroscopic Evidence for a High-Spin Br-Fe(IV)-Oxo Intermediate in the α-Ketoglutarate-Dependent Halogenase CytC3 from Streptomyces journal November 2007
Probing the penicillin sidechain selectivity of recombinant deacetoxycephalosporin C synthase journal May 2001
X-ray Absorption Spectroscopy Structural Investigation of Early Intermediates in the Mechanism of DNA Repair by Human ABH2 journal June 2011
O 2 - and α-Ketoglutarate-Dependent Tyrosyl Radical Formation in TauD, an α-Keto Acid-Dependent Non-Heme Iron Dioxygenase journal February 2003
Alternative Reactivity of an α-Ketoglutarate-Dependent Iron(II) Oxygenase:  Enzyme Self-Hydroxylation journal May 2001
Dioxygen activation by nonheme iron enzymes with the 2-His-1-carboxylate facial triad that generate high-valent oxoiron oxidants journal January 2017
Direct spectroscopic detection of a C-H-cleaving high-spin Fe(IV) complex in a prolyl-4-hydroxylase journal September 2006
Electron Paramagnetic Resonance of Some Sulfur and Selenium Compounds journal October 1964
FIH-1 is an asparaginyl hydroxylase enzyme that regulates the transcriptional activity of hypoxia-inducible factor journal June 2002
Substrate-Triggered Formation and Remarkable Stability of the C−H Bond-Cleaving Chloroferryl Intermediate in the Aliphatic Halogenase, SyrB2 journal May 2009
X-ray Crystal Structure of Escherichia coli Taurine/α-Ketoglutarate Dioxygenase Complexed to Ferrous Iron and Substrates , journal April 2002
O 2 Activation by Non-Heme Iron Enzymes journal November 2016