Cynthia M. Dupureur, Department Chair
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Chemistry & Biochemistry: Summer 2017
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Graduate Student Seminars
Robert W. Murray Lecture
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Professor Gokel attended Tulane University, New Orleans, LA, B.S. chemistry, 1968, University of Southern California, Los Angeles, CA, Ph.D. chemistry with I. K. Ugi, 1971 and UCLA, where he did a postdoctoral fellowship with D.J. Cram, 1972-1974. He served at Penn State, Maryland and Miami prior to heading the Program in Chemical Biology, Washington University School of Medicine, St. Louis. He joined UM-St. Louis as Distinguished Professor in 2006 and also serves as Director of the Center for Nanoscience.
Synthetic cation and anion channels
During the past decade, our lab has developed and elaborated a class of synthetic ion channels called hydraphiles. We use diaza-18-crown-6 macrocycles as head groups and entry portals for ion conduction. Hydrophobic spacer chains connect the headgroups and impart the appropriate length for the hydraphile to span the bilayer. A third, central macrocycle acts as an "ion relay". . These compounds not only function as ion channels in membranes, they enhance the efficacy of FDA-approved antibiotics such as rifampicin, a first line drug used against TB, by up to 16-fold. .
Anion, particularly chloride, permeability is essential for volume, pH, and membrane potential regulation in all cells. We have developed a chloride-selective channel (shown). We are currently studying some very simple tris-arene molecules that have proved to be effective transformation and transfection agents. These non-toxic compounds enhance the transport of DNA across the cellular boundaries of bacteria, yeast, plants, and mammalian cells. Two lab members have founded a company called Genetix Fusion LLC that is developing this technology.
Molecular Capsules and Nanotubes
It has been known for more than a century that phenols and aldehydes react to form macrocycles. We have been developing the chemistry of amphiphilic nanocapsules and nanotubes for drug delivery. The pyrogallolarene compounds have a unique and nearly unexplored chemistry. We have found that they form ion channels and exhibit very unusual amphiphilic properties. The figure below shows a section of nanotube along with the adjacent tubes interlocked with it. The individual elements that form the nanotube also foster ion transport in natural membranes.
Selected Recent Publications
″Supramolecular cation transporters alter root morphology in the Arabidopsis thaliana plant, ″ M. B. Patel, S. Negin, A. Stavri and G. W. Gokel, Inorg. Chim. Acta, 2017 468, 183
″Condensation of plasmid DNA by benzyl hydraphiles and lariat ethers: dependence on pH and chain length,″ J. W. Meisel, M. H. Patel and G. W. Gokel Supramolecular Chem. 2017, A29, 167.
″Antibiotic Potency against E. coli Is Enhanced by Channel-Forming Alkyl Lariat Ethers,″ S. Negin, M. H. Patel, M. R. Gokel, J. W. Meisel and G. W. Gokel, ChemBioChem, 2016, 17, 2153
″Molecules that inhibit efflux pumps in multi-drug resistant bacteria and uses thereof,″ G. W. Gokel, M. R. Gokel, S. Negin and M. B. Patel, U.S. Pat. Appl. Publ. 2016, US 20160361292 A1 20161215.
″Reversal of Tetracycline Resistance in Escherichia coli by Noncytotoxic bis(Tryptophan)s,″ J. W. Meisel, M. H. Patel, E. Garrad, R. A. Stanton and G. W. Gokel, J. Am. Chem. Soc. 2016, 38, 10571
″A Simplified Direct Lipid Mixing Lipoplex Preparation: Comparison of Liposomal-, Dimethylsulfoxide-, and Ethanol-Based Methods,″ J. W. Meisel and G. W. Gokel, Sci. Reports, 2016, 6, 27662
″Synthetic Receptors for Alkali Metal Cations,″ G. W. Gokel and J. W. Meisel. Monographs in Supramolecular Chem. 2015, 14, 86.
″Hydraphiles enhance antimicrobial potency against Escherichia coli, Pseudomonas aeruginosa, and Bacillus subtilis,″ M. B. Patel, E. C. Garrad, A Stavri, M. R. Gokel, S. Negin, J. W. Meisel, Z. Cusumano and G. W. Gokel, Bioorg. & Med. Chem. 2016, 24, 2864
″Biological Activity of Macrocyclic Cation Transporters,″ R. Cantwell, E. C. Garrad, M. R. Gokel, M. J. Hayes, J. W. Meisel, S. Negin, M. B. Patel and G. W. Gokel, Curr. Org. Chem. 2015, 19, 2229.
"The aqueous medium-dimethylsulfoxide conundrum in biological studies″, S. Negin, M. R. Gokel, M. B. Patel, S. L. Sedinkin, D. C. Osborn and G. W. Gokel, RSC Advances 2015, 5, 8088.
"Improved synthesis of benzyl hydraphile synthetic cation", N. S. Curvey, S. E. Luderer, J. K. Walker and G. W. Gokel, Synthesis, 2014, 46, 2771
"Hydraphile synthetic ion channels alter root architecture in Arabidopsis thaliana,” M. B. Patel, A. Stavri, N. S. Curvey and G. W. Gokel, Chem. Commun. 2014,, 50 11562
"Ion transport through bilayer membranes mediated by pyrogallolarenes ," S. Negin, R. Li, O. V. Kulikov, M. M. Daschbach and G. W. Gokel, Inorg. Chim. Acta 2014, 417, 177.
"Morphologies of branched-chain pyrogallolarenes in the solid state," O. V. Kulikov, S. Negin, N. P. Rath and G. W. Gokel, Supramolecular Chem. 2014, 26, 506.
"Synthetic ion channels: From pores to biological applications," G. W. Gokel and S. Negin, Acc. Chem. Res., 2013, 46, 2024.