Department of Chemistry and Biochemistry
- About the Graduate Degrees
- Graduate Programs
- Guidelines for Admission Status
- Graduate Financial Support
- How to Apply
- Pre-Application Form
- Chem Grad Students Association
- Fellowships and Stipends
- Graduate Student Handbook and Forms
- About the Undergraduate Degree
- Pre-Course Assignment
- How to Apply
- Undergraduate Programs
- The UTA Chemistry Channel
- Regular Faculty A-Z
- Adjunct Faculty A-Z
- Emeriti Faculty A-Z
- Retired Faculty A-Z
- Daniel W. Armstrong
- William A. Baker
- Edward Bellion
- Alejandro Bugarin
- Saiful Chowdhury
- Purnendu (Sandy) K. Dasgupta
- Rasika Dias
- Ronald L. Elsenbaumer
- Frank W. Foss
- Robert F. Francis
- Jongyun Heo
- Junha Jeon
- Kayunta Johnson-Winters
- Peter Kroll
- Carl J. Lovely
- Frederick MacDonnell
- Subhrangsu S. Mandal
- Dennis S. Marynick
- Brad S. Pierce
- Martin Pomerantz
- Laszlo Prokai
- Krishnan Rajeshwar
- Jimmy R. Rogers
- Zoltan A. Schelly
- Kevin A. Schug
- E. Thomas Strom
- Norma Tacconi (Retired)
- Seiichiro Tanizaki
- Richard B. Timmons
- Research Interests Grid
- Analytical Chemistry
- Environmental Chemistry
- Inorganic Chemistry
- Medicinal Chemistry
- Organic Chemistry
- Organometallic Chemistry
- Physical Chemistry
- ABOUT US
Office: 350 CPB, Email: firstname.lastname@example.org, Phone: 817-272-3802, FAX: 817-272-3808
Enzymes that use Cofactor F420 -- Structure determination by spectroscopic techniques and X-ray crystallography -- Enzyme kinetics and mechanism by rapid-mixing pre-steady state and steady state methods. -- Investigation of reaction intermediates by kinetic isotope effects.
Kayunta Johnson-Winters, Amanda C. Davis, Anna R. Nordstrom, Gordon Tollin and John H. Enemark, Metallomics, “Effects of Large Scale Amino Acid Substitution in the Polypeptide Tether Connecting the Heme and Molybdenum Domains on Catalysis in Human Sulfite Oxidase,” (2010), Accepted.
Kayunta Johnson-Winters, Gordon Tollin and John H. Enemark, Biochemistry, ”Elucidating the Catalytic Mechanism of Sulfite Oxidizing Enzymes Using Structural, Spectroscopic, and Kinetic Analyses. (2010), Accepted
Rajapakshe A, Johnson-Winters K, Nordstrom AR, Meyers KT, Emesh S, Astashkin AV, Enemark JH., “Characterization of chloride-depleted human sulfite oxidase by electron paramagnetic resonance spectroscopy: experimental evidence for the role of anions in product release” Biochemistry, (2010) 49, 5154-9.
Trevor D. Rapson, Andrei V. Astashkin, Kayunta Johnson-Winters, ,Paul V. Bernhardt, Ulrike Kappler, Arnold M. Raitsimring, John H. Enemark, Journal of Biological Chemistry, “Pulsed EPR investigations of the Mo(V) centers of the R55Q and R55M variants of sulfite dehydrogenase from Starkeya novella” (2010) 15, 505-514
Kayunta Johnson-Winters, Anna Nordstrom, Safia Emesh, Andrei Astashkine, Asha Rajapakshe, Robert Berry, John Yang, Gordon Tollin, K.V. Rajagopolan and John H. Enemark* Biochemistry,” Effects of Interdomain-Tether Length and Flexibility on the Kinetics of Intramolecular Electron Transfer in Human Sulfite Oxidase” (2010) 49, 1290-6
Andrei V. Astashkin, Eric L. Klein, Dmitry Ganyushin, Kayunta Johnson-Winters, Frank Neese , Ulrike Kappler, John H. Enemark, Physical Chemistry Chemical Physics, “Exchangeable oxygens in the vicinity of molybdenum center of the high-pH form of sulfite oxidase and sulfite dehydrogenase,” (2009), 11, 6733 – 6742.
Eric L. Klein, Andrei V. Astashkin, Dmitry Ganyushin, Christoph Riplinger, Kayunta Johnson-Winters, Frank Neese, John H. Enemark, Inorganic Chemistry, “Direct detection and characterization of chloride in the active site of the low-pH form of sulfite oxidase using electron spin echo envelope modulation spectroscopy, isotopic labeling, and density functional theory calculations,” (2009), 48, 4743-52.
Susan Bailey, Trevor Rapson, Kayunta Johnson-Winters, Andrei V. Astashkin and John H. Enemark, Journal of Biological Chemistry, “Molecular Basis for Enzymatic Sulfite Oxidation-How Three Conserved Active Site Residues Shape Enzyme Activity” (2008), 284, 2053-63.
Andrei V. Astashkin, Kayunta Johnson-Winters, Eric L. Klein, Changjian Feng, Heather L. Wilson, K. V. Rajagopalan, Arnold M. Raitsimring, John H. Enemark, Journal of the American Chemical Society, “Structural studies of the molybdenum center of the pathogenic R160Q mutant of human sulfite oxidase by pulsed EPR spectroscopy and 17O and 33S labeling “ (2008), 130, 8471-80.
Andrei V. Astashkin, Kayunta Johnson-Winters, Eric L. Klein, Robert S. Byrne, Russ Hille, Arnold M. Raitsimring, John H. Enemark,, Journal of the American Chemical Society, “Direct demonstration of the presence of coordinated sulfate in the reaction pathway of Arabidopsis thaliana sulfite oxidase using 33S labeling and ESEEM spectroscopy” (2007),129, I14800-10.
Kayunta Johnson-Winters, Vincent M. Purpero, Michael Kavana, and Graham R. Moran, Biochemistry, "The Accumulation of Mulitple Intermediates in the Catalytic Cycle of (4-Hydroxyphenyl)pyruvate Dioxygenase from Streptomyces avermitilis." (2005), 44, 7189-7199.
June M. Brownlee, Kayunta Johnson-Winters, David H.T. Harrison, and Graham R. Moran, Biochemistry, "Structure of the Ferrous Form of (4-Hydroxyphenyl)pyruvate Dioxygenase from Streptomyces avermitilis in Complex with the Therapeutic Herbicide, NTBC” (2004), 43, 6370-6377.
Kayunta Johnson-Winters, Vincent M. Purpero, Michael L. Kavana, Tamara N. Nelson, and Graham R. Moran Biochemistry, "(4-Hydroxyphenyl)pyruvate Dioxygenase from Streptomyces avermitilis: The Basis for Ordered Substrate Addition" (2003), 42, 2072-2080.
Postdoctoral Research June, 2006-July, 2010, University of Arizona, Tucson, Arizona,Project: Kinetics and Spectroscopy of Sulfite Oxidase and Related Molybdenum Enzymes, in the laboratory of Prof. John H. Enemark
PhD, in Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI, May, 2006 Dissertation Title: Structural and Kinetic Characterization of 4-Hydroxyphenylpyruvate Dioxygenase from Streptomyces avermitilis.
Bachelors of Arts. Alverno College, Milwaukee, WI, May 1999, Majors: Biology and Chemistry
Kayunta Johnson- Winters was born in Bastrop, Louisiana, but grew up in Milwaukee, WI. In 1999, Kayunta received her bachelor’s degree from Alverno College, double majoring in Biology and Chemistry. She received her PhD in Biochemistry, under the academic advisory of Prof. Graham R. Moran at the University of Wisconsin-Milwaukee in 2006. At UWM, her studies were on the structure and kinetics of non-heme iron dioxygenases, primarily, the enzyme, 4-Hydroxyphenylpyruvate Dioxygenase (HPPD). She did her postdoctoral studies at the University of Arizona with Regents Professor, Dr. John H. Enemark. There her project was, "Kinetics and Spectroscopy of Sulfite Oxidase and Related Molybdenum Enzymes." At the University of Arizona, she was awarded the national NIH (National Institutes of Health) fellowship, The Ruth L. Kirschstein Service Award. Her current research interests are to characterize F420 Cofactor Dependent Enzymes.
Member: American Chemical Society
Awards: 2007 National Institutes of Health(NIH) Ruth L. Kirschstein National Research Service Award