A5090361351- Metalloenzymes and iron-sulfur proteins
- Metal-Catalyzed Oxygenation Mechanisms
- Magnetism in coordination complexes
- CO2 Reduction Techniques and Catalysts
- Porphyrin and Phthalocyanine Chemistry
- Electrocatalysts for Energy Conversion
- Organic and Molecular Conductors Research
- Redox biology and oxidative stress
- Folate and B Vitamins Research
- Metal complexes synthesis and properties
- Porphyrin Metabolism and Disorders
- Chemical Synthesis and Analysis
- Inorganic and Organometallic Chemistry
- Enzyme Structure and Function
- Inorganic Chemistry and Materials
- Metal-Organic Frameworks: Synthesis and Applications
- Chemical Synthesis and Reactions
- Advanced battery technologies research
- Molecular Junctions and Nanostructures
- Carbon dioxide utilization in catalysis
- Fullerene Chemistry and Applications
- Ammonia Synthesis and Nitrogen Reduction
- Microbial Fuel Cells and Bioremediation
- Organometallic Complex Synthesis and Catalysis
- Sulfur-Based Synthesis Techniques
Montana State University
2011-2024
Museum of the Rockies
2018-2021
Michigan State University
2000-2005
Northwestern University
1989-2005
Simon Fraser University
2005
Emory University
2002
Albany State University
1993-1995
University at Albany, State University of New York
1993-1995
Northwest University
1989-1993
Cerritos College
1979-1988
Pyruvate formate-lyase activating enzyme generates a stable and catalytically essential glycyl radical on G 734 of pyruvate via the direct, stereospecific abstraction hydrogen atom from formate-lyase. The activase performs this remarkable feat by using an iron-sulfur cluster S -adenosylmethionine (AdoMet), thus placing it among AdoMet superfamily enzymes. We report here structures substrate-free substrate-bound forms formate-lyase-activating enzyme, first activase. To obtain structure, we...
The study of magnetic phase transitions in insulating molecular solids provides new insights into mechanisms coupling the solid state and critical phenomena associated with these transitions. Only a few such materials are known to display cooperative properties. use high-spin components would enhance intermolecular spin-spin interactions thus series chargetransfer (CT) salts have been synthesized that utilize spin S = 1 cation, [Mn(C(5)(CH(3))(5))(2)](+) (decamethylmanganocenium). structure...
Catching a radical in action Many enzymes catalyze reactions through the production of intermediates. Radical SAM enzymes, largest superfamily nature, do this by using an iron-sulfur cluster to cleave S-adenosylmethionine and produce intermediate. Using freeze quenching, Horitani et al. were able trap previously unseen intermediate from bacterial pyruvate formate-lyase activating enzyme. Spectroscopy revealed that consists short-lived covalent bond between terminal carbon 5′-deoxyadenosyl...
Radical S-adenosyl-l-methionine (SAM) enzymes comprise a vast superfamily catalyzing diverse reactions essential to all life through homolytic SAM cleavage liberate the highly reactive 5'-deoxyadenosyl radical (5'-dAdo·). Our recent observation of catalytically competent organometallic intermediate Ω that forms during reaction (RS) enzyme pyruvate formate-lyase activating-enzyme (PFL-AE) was therefore quite surprising, and led question its broad relevance in superfamily. We now show PFL-AE...
The 5'-deoxyadenosyl radical (5'-dAdo·) abstracts a substrate H atom as the first step in radical-based transformations catalyzed by adenosylcobalamin-dependent and S-adenosyl-l-methionine (RS) enzymes. Notwithstanding its central biological role, 5'-dAdo· has eluded characterization despite efforts spanning more than half-century. Here, we report generation of RS enzyme active site at 12 K using novel approach involving cryogenic photoinduced electron transfer from [4Fe-4S]+ cluster to...
Pyruvate formate-lyase activating enzyme (PFL-AE) generates the catalytically essential glycyl radical on pyruvate via interaction of active [4Fe−4S]+ cluster with S-adenosylmethionine (AdoMet). Like other members Fe−S/AdoMet family enzymes, PFL-AE is thought to function generation an AdoMet-derived 5'-deoxyadenosyl intermediate; however, mechanistic steps by which this generated remain be elucidated. While all enzymes appear have a unique iron site in [4Fe−4S] cluster, based presence...
Pyruvate formate-lyase activating enzyme (PFL-AE) is a representative member of an emerging family enzymes that utilize iron−sulfur clusters and S-adenosylmethionine (AdoMet) to initiate radical catalysis. Although these have diverse functions, evidence they operate by common mechanism in which [4Fe−4S]+ interacts with AdoMet generate 5'-deoxyadenosyl intermediate. To date, however, it has been unclear whether the cluster simple electron-transfer center or participates directly generation...
Pyruvate formate-lyase activating enzyme (PFL-AE) generates the catalytically essential glycyl radical of PFL. It is a member so-called “radical-SAM superfamily” enzymes that use [4Fe-4S] cluster and S-adenosylmethionine (AdoMet or SAM) to catalyze diverse radical-mediated reactions. Evidence suggests this class operate by common initial steps involving generation an AdoMet-derived adenosyl intermediate, which mechanism remains unresolved. The three-cysteine CX3CX2C cluster-binding motif all...
In an effort to determine the specific protein component(s) responsible for in vitro activation of [FeFe] hydrogenase (HydA), individual maturation proteins HydE, HydF, and HydG from Clostridium acetobutylicum were purified heterologous expressions Escherichia coli. Our results demonstrate that HydF isolated a strain expressing all three is sufficient confer activity inactive heterologously expressed HydA (expressed absence HydG). These represent first with proteins, suggest functions as...
Radical S-adenosyl-l-methionine (SAM) enzymes employ a [4Fe–4S] cluster and SAM to initiate diverse radical reactions via either H-atom abstraction or substrate adenosylation. Here we use freeze-quench techniques together with electron paramagnetic resonance (EPR) spectroscopy provide snapshots of the reaction pathway in an adenosylation catalyzed by enzyme pyruvate formate-lyase activating on peptide containing dehydroalanine residue place target glycine. The proceeds initial formation...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTstar-Porphyrazines: synthetic, structural, and spectral investigation of complexes the polynucleating porphyrazineoctathiolato ligandChristopher S. Velazquez, Glenn A. Fox, William E. Broderick, Kevin Andersen, Oren P. Anderson, Anthony G. M. Barrett, Brian HoffmanCite this: J. Am. Chem. Soc. 1992, 114, 19, 7416–7424Publication Date (Print):September 1, 1992Publication History Published online1 May 2002Published inissue 1 September...
Electron paramagnetic resonance (EPR), electron-nuclear double (ENDOR), and Mössbauer spectroscopies other physical methods have provided important new insights into the radical-SAM superfamily of proteins, which use iron-sulfur clusters S-adenosylmethionine to initiate H atom abstraction reactions. This remarkable chemistry involves generation extremely reactive 5'-deoxyadenosyl radical, same radical intermediate utilized in B12-dependent Although early speculation focused on possibility an...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe mechanism of spin coupling in metallocenium charge-transfer salts: ferromagnetism decamethylchromocenium tetracyanoquinodimethanideWilliam E. Broderick and Brian M. HoffmanCite this: J. Am. Chem. Soc. 1991, 113, 16, 6334–6335Publication Date (Print):July 1, 1991Publication History Published online1 May 2002Published inissue 1 July 1991https://pubs.acs.org/doi/10.1021/ja00016a095https://doi.org/10.1021/ja00016a095research-articleACS...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMetal-encapsulated porphyrazines: synthesis, x-ray crystal structure and spectroscopy of a tetratin-star-nickel(porphyrazine)S8 complexChristopher S. Velazquez, William E. Broderick, Michal Sabat, Anthony G. M. Barrett, Brian HoffmanCite this: J. Am. Chem. Soc. 1990, 112, 20, 7408–7410Publication Date (Print):September 1, 1990Publication History Published online1 May 2002Published inissue 1 September 1990https://doi.org/10.1021/ja00176a059Request...
Radical SAM (RS) enzymes use S-adenosyl-l-methionine (SAM) and a [4Fe–4S] cluster to initiate broad spectrum of radical transformations throughout all kingdoms life. We report here that low-temperature photoinduced electron transfer from the [4Fe–4S]1+ bound in active site hydrogenase maturase RS enzyme, HydG, results specific homolytic cleavage S–CH3 bond SAM, rather than S–C5′ as enzyme-catalyzed (thermal) HydG reaction. This result is stark contrast recent which ET enzyme pyruvate...
Maturation of [FeFe]-hydrogenase (HydA) involves synthesis a CO, CN- , and dithiomethylamine (DTMA)-coordinated 2Fe subcluster that is inserted into HydA to make the active hydrogenase. This process requires three maturation enzymes: radical S-adenosyl-l-methionine (SAM) enzymes HydE HydG, GTPase HydF. In vitro with purified has been possible only when clarified cell lysate was added, presumably providing essential components for DTMA delivery. Here we report using fully defined system...
1/2H and 13C hyperfine coupling constants to 5′-deoxyadenosyl (5′-dAdo•) radical trapped within the active site of S-adenosyl-l-methionine (SAM) enzyme, pyruvate formate lyase-activating enzyme (PFL-AE), both in absence substrate presence a reactive peptide-model PFL substrate, are completely characteristic classical organic free whose unpaired electron is localized 2pπ orbital sp2 C5′-carbon (J. Am. Chem. Soc. 2019, 141, 12139–12146). However, prior electron-nuclear double resonance (ENDOR)...
OspD is a radical
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStructural Evidence for the Expected Jahn-Teller Distortion in Monoanionic C60: Synthesis and X-ray Crystal Structure of Decamethylnickelocenium BuckminsterfullerideWai Chou Wan, Xioahua Liu, Gregory M. Sweeney, William E. BroderickCite this: J. Am. Chem. Soc. 1995, 117, 37, 9580–9581Publication Date (Print):September 1, 1995Publication History Published online1 May 2002Published inissue 1 September...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTConductive molecular crystals from three-dimensional building blocks: synthesis and characterization of tris(bis(ethylenedithio)tetrathiafulvalenium) bis(tris(2-thioxo-1,3-dithiole-4,5-dithiolato)vanadate), [ET]3[V(dmit)3]2, the corresponding tetramethyltetraselenafulvalenium saltWilliam E. Broderick, Ellen M. McGhee, Martin R. Godfrey, Brian Hoffman, James A. IbersCite this: Inorg. Chem. 1989, 28, 15, 2902–2904Publication Date (Print):July 1,...