A5039312032- Metal-Catalyzed Oxygenation Mechanisms
- Microbial metabolism and enzyme function
- Porphyrin and Phthalocyanine Chemistry
- Enzyme Catalysis and Immobilization
- Microbial bioremediation and biosurfactants
- Photosynthetic Processes and Mechanisms
- Tryptophan and brain disorders
- Metalloenzymes and iron-sulfur proteins
- RNA and protein synthesis mechanisms
- Hemoglobin structure and function
- Carbohydrate Chemistry and Synthesis
- Microbial Natural Products and Biosynthesis
- Enzyme Structure and Function
- Chemical Synthesis and Analysis
- Antibiotic Resistance in Bacteria
- Cyclopropane Reaction Mechanisms
- Trace Elements in Health
- Gut microbiota and health
- Supramolecular Self-Assembly in Materials
- Bioinformatics and Genomic Networks
- Computational Drug Discovery Methods
- CO2 Reduction Techniques and Catalysts
- Biochemical and Structural Characterization
- Tuberculosis Research and Epidemiology
- Biochemical and Molecular Research
Seoul National University
2017-2025
Seoul Institute
2020-2021
Government of the Republic of Korea
2020-2021
University of California, San Diego
2014-2017
Massachusetts Institute of Technology
2009-2011
Pennsylvania State University
2010
Pomona College
2010
Emory University
2009
Okazaki Institute for Integrative Bioscience
2007
Stanford Synchrotron Radiation Lightsource
2007
Nonheme oxoiron(IV) complexes of two pentadentate ligands, N4Py (N,N-bis(2-pyridylmethyl)-bis(2-pyridyl)methylamine) and Bn-tpen (N-benzyl-N,N',N'-tris(2-pyridylmethyl)-1,2-diaminoethane), have been generated found to spectroscopic properties similar the closely related tetradentate TPA (tris(2-pyridylmethyl)amine) complex reported earlier. However, unlike complex, a considerable lifetime at room temperature. This greater thermal stability has allowed hydroxylation alkanes with C−H bonds as...
The generation of new enzymatic activities has mainly relied on repurposing the interiors preexisting protein folds because challenge in designing functional, three-dimensional structures from first principles. Here we report an artificial metallo-β-lactamase, constructed via self-assembly a structurally and functionally unrelated, monomeric redox into tetrameric assembly that possesses catalytic zinc sites its interfaces. designed metallo-β-lactamase is functional Escherichia coli periplasm...
The reactions of manganese(III) porphyrin complexes with terminal oxidants, such as m-chloroperbenzoic acid, iodosylarenes, and H(2)O(2), produced high-valent manganese(V)-oxo porphyrins in the presence base organic solvents at room temperature. have been characterized various spectroscopic techniques, including UV-vis, EPR, 1H 19F NMR, resonance Raman, X-ray absorption spectroscopy. combined results indicate that are diamagnetic low-spin (S = 0) species a longer, weaker Mn-O bond than...
Abstract Proteins are versatile natural building blocks with highly complex and multifunctional architectures, self-assembled protein structures have been created by the introduction of covalent, noncovalent, or metal-coordination bonding. Here, we report robust, selective, reversible metal coordination properties unnatural chelating amino acids as sufficient dominant driving force for diverse self-assembly. Bipyridine-alanine is genetically incorporated into a D 3 homohexamer. Depending on...
Efficient and environmentally friendly conversion of light energy for direct utilization in chemical production has been a long-standing goal enzyme design. Herein, we synthesized artificial photocatalytic enzymes by introducing an Ir photocatalyst Ni(bpy) complex to optimal protein scaffold close proximity. Consequently, the generated C–O coupling products with up 96% yields harvesting visible performing intramolecular electron transfer between two catalysts. We systematically modulated...
The catalytic functions of metalloenzymes are often strongly correlated with metal elements in the active sites. However, dioxygen-activating nonheme quercetin dioxygenases (QueD) found various first-row transition-metal ions when swapping inactivates their innate activity. To unveil molecular basis this seemingly promiscuous yet metal-specific enzyme, we transformed manganese-dependent QueD into a nickel-dependent enzyme by sequence- and structure-based directed evolution. Although net...
Mechanistic studies of the aromatic hydroxylation by high-valent iron(IV)-oxo porphyrin π-cation radicals revealed that oxidation involves an initial electrophilic attack on π-system ring to produce a tetrahedral radical or cationic σ-complex. The mechanism was proposed basis experimental results such as large negative Hammett ρ value and inverse kinetic isotope effect. By carrying out labeling studies, oxygen in oxygenated products found derive from iron-oxo intermediates.
We describe the design and evolution of catalytic hydrolase activity on a supramolecular protein scaffold, Zn4:C96RIDC14, which was constructed from cytochrome cb562 building blocks via metal-templating strategy. Previously, we reported that Zn4:C96RIDC14 could be tailored with tripodal (His/His/Glu), unsaturated Zn coordination motifs in its interfaces to generate variant termed Zn8:A104AB34, turn displayed for hydrolysis activated esters β-lactam antibiotics. Zn8:A104AB34 subsequently...
The methane and toluene monooxygenase hydroxylases (MMOH TMOH, respectively) have almost identical active sites, yet the physical chemical properties of their oxygenated intermediates, designated P*, Hperoxo, Q, Q* in MMOH ToMOHperoxo a subclass ToMOH, are substantially different. We review compare structural differences vicinity sites these enzymes discuss which changes could give rise to different behavior Hperoxo Q. In particular, analysis multiple crystal structures reveals that T213...
l-Glutamate is the most abundant and essential excitatory neurotransmitter in nervous system. However, its direct electrochemical detection challenging due to inherently non-electroactive nature. In this study, we redesigned l-glutamate oxidase (GlutOx) by covalently attaching osmium polypyridyl complexes as electron mediators at selected sites. Most engineered enzymes retained their native catalytic activity, while exhibiting significantly altered currents during oxidation, depending on...
Toluene/o-xylene monooxygenase hydroxylase (ToMOH), a diiron-containing enzyme, can activate dioxygen to oxidize aromatic substrates. To elucidate the role of strictly conserved T201 residue during activation T201S, T201G, T201C, and T201V variants ToMOH were prepared by site-directed mutagenesis. X-ray crystal structures all obtained. Steady-state activity, regiospecificity, single-turnover yields also determined for mutants. Dioxygen reduced was explored stopped-flow UV-vis Mössbauer...
Phenol hydroxylase (PH) and toluene/o-xylene monooxygenase (ToMO) from Pseudomonas sp. OX1 require three or four protein components to activate dioxygen for the oxidation of aromatic substrates at a carboxylate-bridged diiron center. In this study, we investigated influence hydroxylases, regulatory proteins, electron-transfer these systems on substrate (phenol; NADH) consumption product (catechol; H2O2) generation. Single-turnover experiments revealed that only complete containing all are...
This study illustrates that a carefully designed bifunctional linker can steer the construction of various protein heterooligomers without extensive sequence optimizations, expanding structural and functional diversity architectures.
We have shown previously that iodosylbenzene-iron(III) porphyrin intermediates (2) are generated in the reactions of oxoiron(IV) pi-cation radicals (1) and iodobenzene (PhI), 1 2 at equilibrium presence PhI, epoxidation olefins by affords high yields epoxide products. In present work, we report detailed mechanistic studies on nature between iodoarenes (ArI), determination reactive species responsible for olefin when two (i.e., 2) a reaction solution, fast oxygen exchange H(2)18O ArI. first...
We report the observation of a novel intermediate in reaction reduced toluene/o-xylene monooxygenase hydroxylase (ToMOHred) T201S variant, presence regulatory protein (ToMOD), with dioxygen. This species is first oxygenated an optical band any toluene monooxygenase. The UV−vis and Mössbauer spectroscopic properties allow us to assign it as peroxodiiron(III) species, T201Speroxo, similar Hperoxo methane Although generates T201Speroxo addition optically transparent ToMOHperoxo, previously...