My research interests cover a wide range of topics, and I am always willing to work with our undergraduate students on various research projects. During my doctoral work at Colorado State University, my research focus was understanding how cellular genes are accessible and transcribed in the context of the extreme chromatin packaging the DNA must undergo in order to fit into the confines of the nucleus. This packaging greatly limits the accessibility of the DNA and generally has a repressive effect on transcription, yet genes must be rapidly located and transcribed when the cell is faced with sudden changes in environmental conditions. This requires the cell to be able to remodel the chromatin in such a way that the genes can be read and thus proteins made. I studied these questions using various techniques, including X-ray crystallography, FRET, and protein complex analysis.
Since coming to Harding, I have been involved in several projects. I have worked to identify and characterize the hormone/protein (FMS) responsible for increased fat metabolism present in the urine of fasting humans/rats and humans with lipodystrophy. Fat Mobilizing Substance (FMS) activity in fasting human urine has been observed at levels comparable to the activity observed in lipodystrophy and anorexic patients.
During the past several years, I have been involved in projects studying wastewater treatment on the International Space Station with funding from the NASA Space Grant Consortium. Human presence in space requires a self-contained biosphere in which astronauts can work and live. For extended missions these closed systems must be able to clean and disinfect the air and water so that it can be reused. One concern for the designers of this system is the containment of biofilms which have been found to build up on system components and valves. Our research focuses on enhancing the current system of wastewater treatment in space with a reactive oxygen species generator that will break down complex molecules and kill microbes using a combination of UV light and titanium dioxide (which serves as a catalyst). I have also been involved in projects relating to the growth of plants in Martian and lunar regolith. With NASA aiming at sending humans back to the moon, and to Mars within the next 15 years, astronauts will need a way to grow produce food for such a long space flight. Students at Harding are looking at what types of plants can best be grown in Martian and lunar soils to optimize the nutritional content.
Selected Publications:
Hariharalakshmanan, Ranjitha, Ungerbuehler, Dakota, Burke, Thomas, White, Cindy, and Karabacak, Tansel (2022) ZnO nanostructures by hot water treatment for photocatalytic bacterial disinfection. MRS Advances. https://doi.org/10.1557/s43580-022-00305-3
Bao, Y., White, C.L., Luger, K. (2006) Nucleosome Core Particles Containing a Poly (dA∙dT) Sequence Element Exhibit a Locally Distorted DNA Structure. J Mol Biol. Aug 25; 361 (4), 617-24.
White, C.L., and Luger, K. (2004) Defined structural changes occur in a nucleosome upon Amt1 transcription factor binding. J Mol Biol., 342 (5), 1391-402.
White, C.L., Suto, R.K., and Luger, K. (2001) Structure of the yeast nucleosome core particle reveals fundamental changes in internucleosome interactions. EMBO, 20 (18), 5207-5218.
Suto, R.K., Edayathumangalam, R.S., White, C.L., Melander, C., Gottesfeld, J.M., Dervan, P.B., and Luger, K. (2003) Crystal structures of nucleosome core particles in complex with minor groove DNA-binding ligands. J Mol Biol, 326 (2), 371-80.
Muthurajan, U.M., Bao, Y., Forsberg, L.J., Edayathumangalam, R.S., Dyer, P.M., White, C.L., and Luger, K. (2004) Crystal structures of histone SIN mutant nucleosomes reveal altered protein-DNA interactions. EMBO, 23 (2), 260-71.
Dyer, P.N., Edayathumangalam, R.S., White, C.L., Bao, Y., Chakravarthy, S., Muthurajan, U.M., and Luger, K. (2004) Reconstitution of nucleosome core particles from recombinant histones and DNA. Methods Enzymology, 375, 23-44.
Analytical Chemistry is the subsection of chemistry that pursues very practical questions such as 'What is it?' and 'How much is there?' To answer these questions, Analytical Chemistry works under the tenet that every distinct chemical compound is unique from all other compounds in some facet and thus can be identified, separated, and quantified. From this approach all sorts of systems can be studied ranging from what amount of various metals are in our drinking water to identifying indicators that can be linked to a disease progressing (ex. blood glucose levels often indicate untreated diabetes).
My work has involved using mass spectrometry to monitor rapid, microsecond-scale reactions preformed in droplets. This work includes monitoring exchange of isotopes along various sugars to distinguish them upon mass-to-charge detection as well as developing methodology to generate distinctly sized droplets to alter reaction times.
While still developing my research here at Harding, I anticipate my future research to investigate the use of non traditional ionization sources in mass spectrometry (such as paper spray, leaf spray, and silicon spray) to accomplish analysis of in-the-field environments as well as to further study the capabilities of micron sized droplets as reactors for various chemical processes.
My recent awards include:
2022 Baylor Graduate School Outstanding Graduate Research Award in STEM
2023 Baylor Chemistry and Biochemistry Graduate Research Productivity Award
2022 Ron Hites Award from the Journal of the American Society for Mass Spectrometry
Information for 