ChulHee Kang

  1. Professor
Email Addresschkang@wsu.edu
LocationFulmer 264

Biography

Professor of Chemistry

Director of Biomolecular Crystallography Center

Professor of Department of Chemistry/ School of Chemical Engineering and Bioengineering/ Molecular Plant Biology/ School of Biological Sciences/ School of Molecular Biosciences/ Washington Center for Muscle Biology

Education

Research Fellow, 1988-1992
Massachusetts Institute of Technology, Cambridge, MA

Post-Doctoral Study, 1988-1989
Lawrence Berkeley National Laboratory, Berkeley, CA

Ph.D. Biophysics & Chemistry, 1987 University of California, Berkeley, CA

B.S. (1980), M.S. (1982) Physics & Microbiology double major, Seoul National University, Seoul, Korea

Cardiovascular/Pharmacology Projects

The major SR protein, calsequestrin (Casq), binds Ca2+ ions with high capacity (40-80 mol Ca2+), but moderate affinity (Kd =1mM) and releases it with a high off-rate. Therefore, Casq has been proposed as a Ca2+ buffer inside the SR and/or an allosteric sensor of the fall in SR Ca2+ concentration. Cardiac Casq mutations cause of catecholaminergic polymorphic ventricular tachycardia (CPVT), an arrhythmogenic disorder with a high mortality rate. Mutations to skeletal Casq have been also identified as causes or enablers of malignant hyperthermia (MH) and other skeletal muscle diseases, like vacuolar aggregate myopathy and central core disease. In addition, defective post-translational modifications of Casq, have been linked to cardiac pathology. We have been studying the unique mechanism by which Casq regulates SR Ca2+, and provided a basic insight into its Ca2+ sequestration and the altered behavior of post-translationally modified and/or mutated Casq. We have discovered that many pharmaceutical drugs with muscle-related or cardiotoxic side effects, a common side effect seen in many synthetic pharmaceutical drugs, bind to and interfere with the normal functions of Casq.

Our study has provided fundamental mechanism of high capacity Ca2+ sequestration and essential insight into how drugs with notorious muscle-related side effects can be improved and help design more effective treatments for CPVT.

BioFuel

Under the Energy Independence Security Act, the U.S. has established a national goal of replacing 30% of petroleum-based fuels with lignocellulosic fuels by the year 2030. Sorghum is an attractive feedstock that can be grown across much of the U.S. including low-productivity land. The most common process for converting biomass into biofuels is via fermentation of monomeric sugars obtained from cellulose and hemicellulosic polysaccharides in the plant cell walls. The efficiency of c

urrently applied methods for the manufacturing of plant cellulose-based biofuels is significantly hindered by the presence of lignin in the cell wall. Lignin, an aromatic polymer formed from the oxidative coupling of hydroxycinnamyl alcohols and related compounds, shields cellulose from the hydrolytic enzymes. Hence, lignin poses a major challenge to large-scale and economically efficient biofuel production. Therefore, manipulating lignin content and subunit composition, as a way to enhance biomass conv

ersion is a major target of our research, along with ways to boost cellulose content. We approach this with the detailed structural and mechanistic knowledge of every key enzyme in the monolignol biosynthetic pathway, which will facilitate efficient and targeted manipulation of lignin subunit composition and lignin content, while maintaining plant viability. In addition, this detailed knowledge on monolignol biosynthetic enzymes can lead to the synthesis of novel phenolic compounds with antioxidant or plant-prot

ective properties that can enhance the value of the crop. We have already shown successfully the promise of this approach by combining the structural analysis of the sorghum enzymes; caffeoyl-CoA O-methyltransferase (CCoAOMT), cinnamoyl-CoA reductase (CCR),cinnamyl alcohol dehydrogenase (CAD),caffeic acid O-methyltransferase (COMT),  class III peroxidase (PRXIII), phenylalanine ammonia-lyase (PAL), tyrosine ammonia-lyase (TAL), trans-cinnamate-4-hydroxylase (C4H), p-coumarate-3-hydroxylase (C3H) and ferulate-5-hydroxylase (F5H)  and hydroxycinnamoyltransferase (HCT) with enzymatic analysis.

Bioremediation

Several polychlorophenols, such as 2,4,5-, 2,4,6-trichlorophenol (TCP), and pentachlorophenol (PCP) are primarily introduced into the environment through their use as preservatives in the wood industry, as herbicides in agriculture, and as general biocides in consumer products. They persist in the environment because halogen substitution makes them recalcitrant to degradation.

Our research focuses on critical monooxygenases and dioxygenates. We have successfully determined the 3D-structure of many participating enzymes allowing us to investigate and compare the unique activities and substrate specificities of the enzymes using site-directed mutagenesis as well as kinetic and thermodynamic characterizations of the enzyme, cofactor and substate interactions. Determination of the 3-D structures will provide insight about their substrate specificity eventually allowing us to rationally design the active sites of enzymes to obtain desired specificities. The systematic structural and biophysical approaches and the designed mutants will offer information not only for the interaction between its unique substrate and active site amino acid residues but the reaction mechanisms.

Cancer Projects

Intensive efforts are taking place to determine the structures of various cancer-associated proteins and types of damaged DNA, including oxidative and UV damaged, and, ultimately, to develop anticancer drugs. Using complex crystal structures and binding studies, the search for new anti-cancer drugs that are free of side effects, are being carried out. We are also investigating key plant enzymes involved in various pathways, which have important and direct connections with human health such as chemoprotection against various cancers, lowering blood cholesterol levels, and as antifungal/antiviral agents, biocides, antifeedants, and antioxidants. These studies will be used to develop treatments for various cancers.

Publications

  • Zhang B, Lewis KM, Abril A, Davydov DR, Vermerris W, Sattler SE & Kang C (2020) Structure and Function of the Cytochrome P450 Monooxygenase, Cinnamate 4-hydroxylase (C4H1) from Sorghum bicolorPlant Physiol. 183: 957-973.
  • Lewis KM, Greene CL, Sattler SA, Youn B, Xun L & Kang C (2020) The structural basis of the binding of various aminopolycarboxylates by the periplasmic EDTA-binding protein EppA from Chelativorans BNC1.Int J Mol Sci. 21: E3940. doi: 10.3390/ijms21113940
  • Zhang B, Munske G, Timokhin V, Ralph J, Davydov D, Vermerris W, Sattler SA & Kang C (2022) Functional and structural insight into the flexibility of cytochrome P450 reductases from Sorghum bicolor and its implications for lignin composition. J Biol Chem. 298: 101761. doi: 10.1016/j.jbc.2022.101761.
  • Ahmadvand P, Avillan JJ, Lewis JA, Call DR & Kang C (2022) Characterization of Interactions between CTX-M-15 and Clavulanic Acid, Desfuroylceftiofur, Ceftiofur, Ampicillin, and Nitrocefin. Int J Mol Sci. 23: 5229. doi: 10.3390/ijms23095229.
  • Zhang B, Lewis JA, Vermerris W, Sattler SE & Kang C. (2023) A sorghum ascorbate peroxidase with four binding sites has activity against ascorbate and phenylpropanoids.  Plant Physiol. 192: 102-118. doi: 1 0.1093/plphys/kiac604.
  • Zhang B, Lewis JA, Sattler SE Sarath G & Kang C. (2023) Activity of Cytosolic Ascorbate Peroxidase (APX) from Panicum virgatum against Ascorbate and Phenylpropanoids.   J Mol Sci. 24: 1778.doi: 10.3390/ijms24021778.
  • Lewis JA, Zhang B, Harza R, Palmer N, Sarath G, Sattler SE, Twigg P, Vermerris W & Kang C (2023) Structural Similarities and Overlapping Activities among Dihydroflavonol 4-Reductase, Flavanone 4-Reductase, and Anthocyanidin Reductase Offer Metabolic Flexibility in the Flavonoid Pathway. Int J Mol Sci.24: doi: 10.3390/ijms241813901