中文 English

Electron Spin Resonance in free radical enzymology and in material characterization

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 – 2022	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 – 今	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 (Lab rotation, 2002 – present)

Quantum Mechanics I & II (2004 – 2007)

Undergraduate courses

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

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

Research Interests

Our research interests are in the area of mechanistic radical enzymology and electronic structure of solid state materials, with emphases on application of advanced EPR techniques and DFT based computations to characterize paramagnetic species. Recently, we focus on:

(1) The increasing ubiquity of 5'-deoxyadenosyl-5'-yl radical (5'-dAdo*), as a primary high energy radical in initiating enzymatic reaction across all kingdoms of life, has promoted a continuous momentum of research activity.By different chemical tactics, 5'-deoxyadenosylcobalamin (5'-dAdoCbl) and S-adenosyl-L-methionine (SAM) serve as the biological source for 5'-dAdo*. The lysine 5,6-aminomutase (5'-dAdoCbl) and the glutamate 2,3-aminomutase (SAM) are selected for scrutiny to disclose the beauty of the underlying mechanism by which radical enzymes operate to control the reaction trajectory of 5'-dAdo* exquisitely with specificity. Both enzymes require the participation of pyridoxal-5'-phosphate as another cofactor for the chemically challenging isomerization. The radical chemistries are probed by providing EPR/ENDOR/ESEEM snapshots of the evolving radical states, with various substrates/inhibitors/cofactor analogs. The complexity of radical enzymology is multidisciplinary in nature. We integrate enzymology, organic synthesis, DFT computation and spectroscopic techniques in a theme to address the radical chemistry related problems at molecular level; and,

(2) The second focus of our research is the elucidation of the surface chemistry of TiO2 and g-C3N4. We also synthesize new materials with enhanced charge separation for various applications, by means of doping, heterostructure fabrication, or coupling with transition metal complexes (recently focusing on ruthenium-arene/g-C3N4 conjugate for CO2 reduction). We study the kinetics and dynamics of photogenerated charge carriers on these materials. We avail the necessary biomaterial synthesis unit in our lab and are searching the active-sites on several other semiconductors and developing stable methods for their conjugations with biomaterials, through fundamental mechanistic studies.

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, 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)
2	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)
3	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)
4	DB Nimbalkar, M Stas, SS Hou, SC Ke, JJ Wu, Microscopic Revelation of Charge Trapping Sites in Polymeric Carbon Nitrides for Enhanced Photocatalytic Activity by Correlating with Chemical and Electronic Structures, ACS Appl. Mater. Interfaces, 11, 21, 19087 (2019)
5	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)
6	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)
7	PVRK Ramacharyulu, SJ Abbas, SC Ke, Enhanced charge separation and photoactivity in heterostructured g-C3N4: a synergistic interaction in environmental friendly CaO/g-C3N4, Catal. Sci. Technol., 7, 4940 (2017)
8	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)
9	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)
10	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)
11	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)
12	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)
13	TH Wang, YH Chen, JY Huang, KC Liu, SC Ke, HA Chu, Enzyme kinetics, inhibitors, mutagenesis and electron paramagnetic resonance analysis of dual-affinity nitrate reductase in unicellular N2-fixing cyanobacterium Cyanothece sp PCC8801, Plant Physiology and Biochemistry, 49, 1369 (2011)
14	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)
15	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)
16	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)
17	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

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