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Georges Chreifi, PhD

Assistant Professor, Biology
Unit: Biology, College of Humanities and Sciences, School of Sciences and Math
Location: Tigerville

"Do not be conformed to this world, but be transformed by the renewal of your mind, that by testing you may discern what is the will of God, what is good and acceptable and perfect." —Romans 12:2
  • Teaching & Education

    I teach courses in Biochemistry, Cell and Molecular Biology, Human Biology, and Introductory Biology.

    BS, Biochemistry, Concordia University
    PhD, Biological Sciences, University of California Irvine
    Postdoctoral Scholar, California Institute of Technology

  • Professional Experience

    Prior to arriving at NGU, I conducted postdoctoral research at Caltech using state-of-the-art cryo-electron microscopy techniques to visualize whole bacterial cells and multi-protein nanomachines. My professional experience also includes teaching courses in Molecular Biology, Biochemistry, and Microbiology at several institutions, including University of California Irvine, Golden West College, and Chapman University.

  • Selected Publications
    • Kaplan, M., Oikonomou, C.M., Wood, C.R., Chreifi, G., Ghosal, D., Dobro, M.J., Yao, Q., Pal, R.R., Baidya, A.K., Liu, Y. and Maggi, S., 2022. Discovery of a novel inner membrane-associated bacterial structure related to the flagellar type III secretion system. Journal of bacteriology, 204(8), pp.e00144-22.
    • Kaplan, M., Oikonomou, C.M., Wood, C.R., Chreifi, G., Subramanian, P., Ortega, D.R., Chang, Y.W., Beeby, M., Shaffer, C.L. and Jensen, G.J., 2022. Novel transient cytoplasmic rings stabilize assembling bacterial flagellar motors. The EMBO Journal, 41(10), p.e109523.
    • Kaplan, M., Chreifi, G., Metskas, L.A., Liedtke, J., Wood, C.R., Oikonomou, C.M., Nicolas, W.J., Subramanian, P., Zacharoff, L.A., Wang, Y. and Chang, Y.W., 2021. In situ imaging of bacterial outer membrane projections and associated protein complexes using electron cryo-tomography. Elife, 10.e73099.
    • Kaplan, M., Wang, Y., Chreifi, G., Zhang, L., Chang, Y.W. and Jensen, G.J., 2021. Programmed flagellar ejection in Caulobacter crescentus leaves pl-subcomplexes. Journal of Molecular Biology, 433(13), p.167004.
    • Chreifi, G., Chen, S. and Jensen, G.J., 2021. Rapid tilt-series method for cryo-electron tomography: Characterizing stage behavior during FISE acquisition. Journal of Structural Biology, 213(2), p.107716.
    • Kaplan, M., Nicolas, W.J., Zhao, W., Carter, S.D., Metskas, L.A., Chreifi, G., Ghosal, D. and Jensen, G.J., 2021. In situ imaging and structure determination of biomolecular complexes using electron cryo-tomography. Methods in Molecular Biology 2215, pp.83-111.
    • Gorasia, D.G., Chreifi, G., Seers, C.A., Butler, C.A., Heath, J.E., Glew, M.D., McBride, M.J., Subramanian, P., Kjaer, A., Jensen, G.J. and Veith, P.D., 2020. In situ structure and organisation of the type IX secretion system. BioRxiv.
    • Treuner-Lange, A., Chang, Y.W., Glatter, T., Herfurth, M., Lindow, S., Chreifi, G., Jensen, G.J. and Søgaard-Andersen, L., 2020. PilY1 and minor pilins form a complex priming the type IVa pilus in Myxococcus xanthus. Nature communications, 11(1), pp.1-14.
    • Cinelli, M.A., Reidl, C.T., Li, H., Chreifi, G., Poulos, T.L. and Silverman, R.B., 2020. First Contact: 7-Phenyl-2-Aminoquinolines, Potent and Selective Neuronal Nitric Oxide Synthase Inhibitors That Target an Isoform-Specific Aspartate. Journal of medicinal chemistry, 63(9), pp.4528-4554.
    • Do, H.T., Li, H., Chreifi, G., Poulos, T.L. and Silverman, R.B., 2019. Optimization of blood–brain barrier permeability with potent and selective human neuronal nitric oxide synthase inhibitors having a 2-aminopyridine scaffold. Journal of medicinal chemistry, 62(5), pp.2690-2707.
    • Chreifi, G., Chen, S., Metskas, L.A., Kaplan, M. and Jensen, G.J., 2019. Rapid tilt-series acquisition for electron cryotomography. Journal of structural biology, 205(2), pp.163-169.
    • Li, H., Evenson, R.J., Chreifi, G., Silverman, R.B. and Poulos, T.L., 2018. Structural basis for isoform selective nitric oxide synthase inhibition by thiophene-2-carboximidamides. Biochemistry, 57(44), pp.6319-6325.
    • Do, H.T., Wang, H.Y., Li, H., Chreifi, G., Poulos, T.L. and Silverman, R.B., 2017. Improvement of cell permeability of human neuronal nitric oxide synthase inhibitors using potent and selective 2-aminopyridine-based scaffolds with a fluorobenzene linker. Journal of medicinal chemistry, 60(22), pp.9360-9375.
    • Hollingsworth, S.A., Nguyen, B.D., Chreifi, G., Arce, A.P. and Poulos, T.L., 2017. Insights into the dynamics and dissociation mechanism of a protein redox complex using molecular dynamics. Journal of chemical information and modeling, 57(9), pp.2344-2350.
    • Pensa, A.V., Cinelli, M.A., Li, H., Chreifi, G., Mukherjee, P., Roman, L.J., Martásek, P., Poulos, T.L. and Silverman, R.B., 2017. Hydrophilic, potent, and selective 7-substituted 2-aminoquinolines as improved human neuronal nitric oxide synthase inhibitors. Journal of medicinal chemistry, 60(16), pp.7146-7165.
    • Chreifi, G., Dejam, D. and Poulos, T.L., 2017. Crystal structure and functional analysis of Leishmania major Journal of Biological Inorganic Chemistry, 22(6), pp.919-927.
    • Cinelli, M.A., Li, H., Chreifi, G., Poulos, T.L. and Silverman, R.B., 2017. Nitrile in the hole: discovery of a small auxiliary pocket in neuronal nitric oxide synthase leading to the development of potent and selective 2-aminoquinoline inhibitors. Journal of medicinal chemistry, 60(9), pp.3958-3978.
    • Chreifi, G. and Poulos T.L. Cytochrome c Peroxidase. Encyclopedia of Inorganic and Bioinorganic Chemistry 2017.
    • Chreifi, G., Baxter, E.L., Doukov, T., Cohen, A.E., McPhillips, S.E., Song, J., Meharenna, Y.T., Soltis, S.M. and Poulos, T.L., 2016. Crystal structure of the pristine peroxidase ferryl center and its relevance to proton-coupled electron transfer. Proceedings of the National Academy of Sciences, 113(5), pp.1226-1231.
    • Fields, J.B., Hollingsworth, S.A., Chreifi, G., Heyden, M., Arce, A.P., Magaña-Garcia, H.I., Poulos, T.L. and Tobias, D.J., 2015. “Bind and crawl” association mechanism of Leishmania major peroxidase and cytochrome c revealed by Brownian and molecular dynamics simulations. Biochemistry, 54(49), pp.7272-7282.
    • Chreifi, G., Hollingsworth, S.A., Li, H., Tripathi, S., Arce, A.P., Magaña-Garcia, H.I. and Poulos, T.L., 2015. Enzymatic mechanism of Leishmania major peroxidase and the critical role of specific ionic interactions. Biochemistry, 54(21), pp.3328-3336.
    • Mukherjee, P., Li, H., Sevrioukova, I., Chreifi, G., Martásek, P., Roman, L.J., Poulos, T.L. and Silverman, R.B., 2015. Novel 2, 4-disubstituted pyrimidines as potent, selective, and cell-permeable inhibitors of neuronal nitric oxide synthase. Journal of medicinal chemistry, 58(3), pp.1067-1088.
    • Li, H., Jamal, J., Plaza, C., Pineda, S.H., Chreifi, G., Jing, Q., Cinelli, M.A., Silverman, R.B. and Poulos, T.L., 2014. Structures of human constitutive nitric oxide synthases. Acta Crystallographica Section D: Biological Crystallography, 70(10), pp.2667-2674.
    • Chreifi, G., Li, H., McInnes, C.R., Gibson, C.L., Suckling, C.J. and Poulos, T.L., 2014. Communication between the zinc and tetrahydrobiopterin binding sites in nitric oxide synthase. Biochemistry, 53(25), pp.4216-4223.
    • Kang, S., Tang, W., Li, H., Chreifi, G., Martásek, P., Roman, L.J., Poulos, T.L. and Silverman, R.B., 2014. Nitric oxide synthase inhibitors that interact with both heme propionate and tetrahydrobiopterin show high isoform selectivity. Journal of medicinal chemistry, 57(10), pp.4382-4396.
    • Cinelli, M.A., Li, H., Chreifi, G., Martásek, P., Roman, L.J., Poulos, T.L. and Silverman, R.B., 2014. Simplified 2-aminoquinoline-based scaffold for potent and selective neuronal nitric oxide synthase inhibition. Journal of medicinal chemistry, 57(4), pp.1513-1530.
    • Huang, H., Li, H., Yang, S., Chreifi, G., Martásek, P., Roman, L.J., Meyskens, F.L., Poulos, T.L. and Silverman, R.B., 2014. Potent and selective double-headed thiophene-2-carboximidamide inhibitors of neuronal nitric oxide synthase for the treatment of melanoma. Journal of medicinal chemistry, 57(3), pp.686-700.
    • Jing, Q., Li, H., Chreifi, G., Roman, L.J., Martásek, P., Poulos, T.L. and Silverman, R.B., 2013. Chiral linkers to improve selectivity of double-headed neuronal nitric oxide synthase inhibitors. Bioorganic & medicinal chemistry letters, 23(20), pp.5674-5679.
    • Li, H., Jamal, J., Chreifi, G., Venkatesh, V., Abou-Ziab, H. and Poulos, T.L., 2013. Dissecting the kinetics of the NADP+–FADH2 charge transfer complex and flavin semiquinones in neuronal nitric oxide synthase. Journal of inorganic biochemistry, 124, pp.1-10.
  • Selected Awards Received

    2015 – Howard A Schneiderman Fellowship Award

  • My Story

    My interest in science really grew from the study of biochemistry. As a graduate student studying the structures of biological molecules, I was amazed by the intricacies and beauty of biological designs. I became fascinated by how the many thousands of exceedingly complex biochemical reactions that occur within living organisms are coordinated with such perfection and harmony. The complexity required for even a single bacterium to sustain itself is breathtaking, let alone larger, more complex organisms such as an insect or animal.

    By studying these biochemical reactions at higher levels of detail, it became clear that they are facilitated by biological machines of remarkable elegance. I was also astonished by how these molecular machines resemble in many ways the machines made by human engineers. In fact, natural designs continue to inspire and help optimize human designs. These are just a few of the many elements that have convinced me that God is the creator and designer of everything in nature.

    By studying biology, we get a glimpse into the mind of God, discovering the beauty and complexity of His designs. I am convinced that science can be enjoyed more deeply by approaching it from that viewpoint, and I am passionate about teaching and mentoring students in Biology for these very reasons. I believe that science as an intellectual pursuit is essential and can strengthen one’s faith in the creator of science, as it has for me.

    My goal is to help students grow so they can excel in the work God has called them to do. By working at North Greenville University, I get to help my students develop their intellectual abilities, guiding them to become critical thinkers skilled at creating and refining ideas, and enhancing their appreciation for God’s wisdom in his natural designs.

    Favorite Course to Teach:

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