中文 Ú English

Electron Spin : Radical Enzymes and Nanomaterials for Sustainable Catalysis

Shyue-Chu Ke (柯學初)

Professor, Physics Department

National Dong Hwa University (NDHU)

(Division of research planning and coordination, R&D office)

Hualien, 97401 Taiwan

Email: ke@gms.ndhu.edu.tw;

Voice: (886)(3) 890-3705

Professional Career Developments

2021	First-class academic medal (NDHU)
2021	Second-class administrative medal (NDHU)
2019 – 2023	Principal investigator, Science Vanguard Research Program, Ministry of Science and Technology, Taiwan
2020 – 2026	Distinguished professor award, NDHU, Taiwan
2010 – 2016	Distinguished professor award, NDHU, Taiwan
2003, 2013, 2016	Excellence in teaching award, College of science and engineering, NDHU, Taiwan
2007 – 2010	Director, Nanotechnology Research Center, NDHU, Taiwan
2007 – now	Professor, NDHU, Taiwan
2003	Honorary Scholar, Biochemistry department, University of Wisconsin-Madison, USA
2003 – 2007	Associate professor, NDHU, Taiwan
1999 – 2003	Assistant professor, NDHU, Taiwan
1998 – 1999	Research assistant professor, Emory University, Atlanta, GA, USA
1997 – 1998	Postdoc, Emory University, Atlanta, GA, USA
1995 – 1997	Postdoc, Medical School, University of Alabama at Birmingham, USA
1991 – 1995	Ph.D., University of Alabama at Birmingham, USA

Teaching @ NDHU

Graduate courses

Biophysics I & II (2000 – present)

Advanced Physical Methods in Material and Biological Systems (2002 – present)

Quantum Mechanics I & II (2004 – 2007)

Undergraduate courses

Experimental Techniques in Physics (2025 – present)

College Physics (1999 – 2004; 2010 – present)

General Physics Laboratory (2008 – 2017, 2019 – present)

Experimental Physics (III) (2000 – 2006)

Experimental Physics (IV) (2006)

Physics in Life Science (General Education Center, 2000 – 2001)

Teaching @ Tzu Chi University (Adjunct Professor)

Physics in biology and medicine (School of Medicine, 2012 – 2017)

Research Interests and Focus

Our laboratory is dedicated to advancing 「catalysis science」 at the molecular level, wherein fundamental discoveries not only deepen our understanding of natural catalysts but also inspire the forward-looking design of next-generation catalysts. The complexity of catalysis science is inherently multidisciplinary. Excelling the traditional boundaries of physics, chemistry, materials science, and biochemistry, we have established a unique interdisciplinary platform to address global challenges in radical enzymology, sustainable energy, and environmental remediation. Our research centers on three main areas:

1. Radical Enzymology

We focus on the 5′-deoxyadenosyl radical (5′-dAdo*), a ubiquitous and highly reactive spin-bearing species that stands at the forefront of modern enzymology. By different chemical tactics, 5'-deoxyadenosylcobalamin (5'-dAdoCbl) and S-adenosyl-L-methionine (SAM) serve as the biological source for 5'-dAdo*. As model systems, we study 5′-dAdoCbl-dependent lysine 5,6-aminomutase and SAM-dependent glutamate 2,3-aminomutase, both of which require pyridoxal 5′-phosphate (5′-PLP) as an auxiliary cofactor to drive catalysis. We synthesize and isotope-label substrates, inhibitors, and cofactors, and employ electron spin resonance (ESR), electron–nuclear double resonance (ENDOR), and electron spin echo (ESE) spectroscopies, complemented by density functional theory (DFT) calculations, to analyze spin–nuclear hyperfine structures, spin–spin and spin–lattice interactions, thereby elucidating radical structural features and their interactions with proteins. This allows us to reconstruct the complete reaction cascade and uncover how radical enzymes specifically and exquisitely control the high-energy 5′-dAdo* trajectory to achieve challenging covalent bond cleavage and formation.

2. Nanomaterials Catalysis

We investigate charge separation and interfacial electron transfer mechanisms in nanomaterials to develop innovative photocatalysts with high efficiency and stability. Our strategies include band-gap engineering (copolymerization, doping, and heterostructure design) and transition-metal complex coupling (e.g., Ru–arene organometallic/g-C₃N₄ conjugates), enabling solar-driven hydrogen production, CO₂ reduction, or pollutant degradation. We also build multifunctional catalytic platforms for organic synthesis, enabling efficient CO₂ insertion, CO₂ cycloaddition, three-component coupling, [3+2] click reactions, and Knoevenagel condensations. We establish a green catalytic system that valorizes waste eggshells to synthesize 5′-PLP derivatives, underscoring the principles of sustainable chemistry. Recently, our “All-in-One” photocatalytic reaction center have achieved world-record quantum yields for solar hydrogen production.

Currently, we are engineering a photo-biohybrid by covalently linking cytoplasmic nitrate reductase (NarB) to benzoic acid-functionalized g-C₃N₄. This “enzyme–bifunctional linker–semiconductor” system enables visible-light-driven reduction of hazardous nitrate contaminants in water. NarB was selected because its [4Fe–4S] cluster is mechanistically highly compatible with solar-driven electron transfer. These proofs of concept, enabled by deep insights into protein structure and heterogeneous material interactions, establish new design principles for catalytic materials.

3. Spectroscopic and Analytical Methods

We design and build a custom nanosecond-resolved pulsed electron spin echo spectrometer and develop quantum mechanical software to elucidate spin–spin coupling mechanisms in enzymes. We also build a custom Raman spectrometer and integrate classical normal coordinate analysis with DFT-based calculation to simulate vibrational spectra. By combining TEM-based nanostructural characterization with tailored simulations of spin–orbit split XPS spectra, we highlight the importance of incorporating realistic structural features in surface analyses and provide fresh perspectives on nanoscale catalyst electronic structures.

We also employ molecular docking and biophysical chemistry techniques to investigate the anticancer activity and selectivity of Ru–arene organometallic complexes.

Vision and Training

Our vision is to shape the future of catalysis science: unraveling the underlining principles of radical enzyme catalysis and developing green catalytic materials capable of converting sunlight and waste into clean energy and high-value chemicals.

We provide students and researchers with comprehensive interdisciplinary training spanning from genetic and protein engineering, organic and nanomaterials synthesis, spectroscopy and theoretical computation, to high-frequency electromagnetic wave circuit design. This unique training equips students and researchers with rare, highly transferable skills and prepares them to tackle the frontier challenges in science and technology. We warmly welcome students and researchers from all backgrounds to join our journey.

Research Facilities

Biochemical-chemical facilities for mutagenesis, cell culture, protein purification, material synthesis, and sample manipulation for spectroscopic studies, HPLC, GC, UV-Visible spectrometer, Bruker EMX continuous wave EPR and ENDOR spectrometer, home-built Pulsed ESR spectrometer, home-built Raman spectrometer, and Gaussian 09 and GAMESS for computations. Other facilities (XRD, XPS, Mass, SEM, TEM ...) are available in campus.

Open Searches

Postdoctoral position or research assistant position at Master or Ph.D. level are available in the field of mechanistic free radical enzymology, nanomaterial chemistry, and pulsed ENDOR instrumentation. The appointments are for up to 4 years with a salary according to Taiwan Ministry of Science and Technology salary scale. Inquiries, along with your CV, can be addressed to ke@gms.ndhu.edu.tw

Graduate/undergraduate students

The education and training of students is an integral part of this laboratory. Dissertation projects are available in the field of radical enzymology, nanomaterial fabrication/chemistry, and EPR spectroscopy (microwave technology/instrumentation/programming). These are multidisciplinary in nature. We welcome students from other departments. Students would have the opportunity to master a diverse array of skills that are highly conducive to their professional developments. Please contact me at ke@gms.ndhu.edu.tw if you would like to know more about research opportunities in this laboratory.

Acknowledgement

We are grateful to the Ministry of Science and Technology in Taiwan for supporting our research (1999 – present).

Selected Publications

1	JR Chen, SC Ke, An all-in-one cytosine fused dihydroisoquinoline reaction center with ultralow Pt loading for excellent solar-to-hydrogen production, Applied Catalysis B: Environmental and Energy 357, 124309, (2024)
2	Ragesh Nath R, SC Ke, Boosting the Photocatalytic Performance of Swiftly Produced Carbon Nitride: Impact of Cyano Group and Oxygen Doping within the Matrix, International Journal of Hydrogen Energy 83, 276-289, (2024)
3	M Muralisankar, JR Chen, JR Haribabu, SC Ke, Effective and Selective Ru (II)-Arene Complexes Containing 4, 4′-Substituted 2, 2′ Bipyridine Ligands Targeting Human Urinary Bladder Cancer Cells, Int. J. Mol. Sci, Vol.24, No.15, 11896, (2023)
4	S Yesmin, SJ Abbas, SC Ke, A Powerful and Multifunctional Catalyst for Organic Synthesis, Transformation, and Environmental Remediation: A polyImidazole Supported Trimetallic Catalyst, Applied Catalysis B: Environmental 316, 121629, (2022)
5	JR Chen, TX Ke, PA. Frey, SC Ke, Electron Spin Echo Envelope Modulation Spectroscopy Reveals How Adenosylcobalamin-Dependent Lysine 5,6-Aminomutase Positions the Radical Pair Intermediates and Modulates Their Stabilities for Efficient Catalysis, ACS Catal 11, 14352−14368, (2021)
6	SR Sahoo, SC Ke, Spin-orbit coupling effects in Au 4f core-level electronic structures in supported low-dimensional gold nanoparticles, Nanomaterials 11, 554-568 (2021)
7	DB Nimbalkar, PVRK Ramacharyulu, SR Sahoo, JR Chen, CM Chang, A Maity, SC Ke, Dual Roles of [NCN]^2- on Anatase TiO2: A Fully Occupied Molecular Gap State for Direct Charge Injection into the Conduction Band and an Interfacial Mediator for the Covalent Formation of Heterostructured g-C3N4/a-TiO2 Nanocomposite, Applied Catalysis B: Environmental 273 119036, (2020)
8	JR Chen, SC Ke, Magnetic Field Effect on Coenzyme B12 and B6 -Codependent Lysine 5,6-Aminomutase: Switching of J-Resonance Through a Kinetically Competent Radical-Pair Intermediate, Phys. Chem. Chem. Phys. 20, 13068 (2018)
9	SR Sahoo, PVRK Ramacharyulu, SC Ke, Impact of Nonideal Nanoparticles on X-ray Photoelectron Spectroscopic Quantitation: An Investigation Using Simulation and Modeling of Gold Nanoparticles, Analytical Chemistry 90, 1621 (2018)
10	SJ Abbas, PVRK Ramacharyulu, HH Lo, SI Ali, SC Ke, A catalytic approach to synthesis of PLP analogs and other environmental protocols in a single handed CaO/TiO2 green nanoparticle, Applied Catalysis B: Environmental, 210, 276 (2017)
11	HH Lo, HH Lin, AN Maity, SC Ke, The Molecular Mechanism of the Open-Closed Protein Conformational Cycle Transitions and Coupled Substrate Binding, Activation and Product Release Events in Lysine 5,6-Aminomutase, Chemical Communications, 52, 6399 (2016)
12	AN Maity, HH Lin, HS Chiang, HH Lo, SC Ke, The Reaction of PLP-NO with Lysine 5,6-Aminomutase: Enzyme Flexibility towards Cofactor Analog, ACS Catalysis, 5, 3093 (2015)
13	YH Chen, AN Maity, PA Frey, SC Ke, Mechanism Based Inhibition Reveals Transitions Between Two Conformational States in the Action of Lysine 5,6-Aminomutase: A Combination of EPR , ENDOR and DFT Study, J. Am. Chem. Soc., 135, 788 (2013)
14	AN Maity, AC Shaikh, S Srimurugan, CJ Wu, C Chen, SC Ke, Synthesis of 4-thia-[6-13C]lysine from [2-13C]glycine: access to site-directed isotopomers of 2-aminoethanol, 2-bromoethylamine and 4-thialysine, Amino Acids, 42, 309 (2012)
15	YH Chen, AN Maity, YC Pan, PA Frey, SC Ke, Radical Stabilization is Crucial in the Mechanism of Action of Lysine 5,6-Aminomutase: Role of Tyrosine-263a as Revealed by Electron Paramagnetic Resonance Spectroscopy, J. Am. Chem. Soc., 133, 17152 (2011)
16	NO Gopal, HH Lo, SC Sheu, SC Ke, A Potential Site for Trapping Photogenerated Holes on Rutile TiO2 Surface as Revealed by EPR Spectroscopy: An Avenue for Enhancing Photocatalytic Activity, J. Am. Chem. Soc., 132, 10982 (2010)
17	NO Gopal, HH Lo, SC Ke, Chemical State and Environment of Boron Dopant in B,N-Codoped Anatase TiO2 Nanoparticles: An Avenue for Probing Diamagnetic Dopants in TiO2 by Electron Paramagnetic Resonance Spectroscopy, J. Am. Chem. Soc., 130, 2760 (2008)
18	RJ Dai, SC Ke, Detection and Determinants of the {Fe(NO)2} core vibrational features in Dinitrosyl-Iron complexes from Experiment, Normal Coordinate Analysis and Density Functional Theory: An Avenue for Probing the Nitric Oxide Oxidation State, J. Phys. Chem. B, 111, 2335 (2007)

Hobby outside the college: Carpentry