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College of Arts and Sciences

Department of Chemistry

UVM Chemistry Research: Matthew Liptak

Matthew D. Liptak

Liptak photo

Matthew D. Liptak, Ph.D., Assistant Professor of Chemistry

  • Ph.D., University of Wisconsin-Madison, 2008
  • postdoctoral fellowship, University of Rochester, 2008-2011
  • Assistant Professor of Chemistry, University of Vermont, August 2011
  • Curriculum vitae
Area of expertise

inorganic, bioinorganic and physical inorganic chemistry

Contact Information

Email: Matthew.Liptak@uvm.edu

Phone: (802) 656-0161

Office: Cook Rm A116

Research

Metal-containing proteins, or metalloproteins, have a diverse array of important functions throughout nature. Many of these functions are governed by electronic structure, the locations and energies of electrons within a molecule. Researchers in the Liptak group investigate the electronic structure of metalloproteins using both spectroscopy and theory. This information helps us understand native function of metalloproteins, introduce novel enzyme functions, and identify the key structural features of undesirable natural functions.

We use a variety of spectroscopic techniques to investigate metalloproteins, including magnetic circular dichroism (MCD) and nuclear magnetic resonance (NMR). MCD spectroscopy allows us to probe any transition metal center and its coordination environment. We use NMR spectroscopy to study the polypeptide environment, including the critical interactions within the protein active site, in both diamagnetic and paramagnetic metalloproteins. These spectroscopic data are interpreted within the framework of electronic structure theory calculations, which allow us to predict the electronic structure, and thus the resulting spectra, for a given metalloprotein state. Researchers in the Liptak group augment their understanding of metalloprotein structure-function relationships using a variety of biochemical techniques, including site-directed mutagenesis and recombinant protein expression in Escherichia coli.

MCD & NMR NMR HSQC plot

One area of interest in the Liptak group is metal tetrapyrrole biosynthesis. We study a class of enzymes called chelatases, which catalyze metal insertion into tetrapyrroles, with the long term goal of designing synthetic chelatases that can catalyze the biosynthesis of any metal tetrapyrrole. These metal tetrapyrrole products are exciting candidates for a variety of applications, including light energy harvesting, hydrogen evolution, bioremediation, and non-linear optics.

Another area of interest is enzymatic metal tetrapyrrole degradation. Several species of pathogenic bacteria harvest iron from iron tetrapyrrole-containing proteins of their host. We use our spectroscopic and theoretical approach to identify unique structural and electronic features of metal tetrapyrrole degrading enzymes from pathogenic bacteria with the long-term goal of supporting the discovery of new antibiotics.

The Liptak group is also interested in developing and utilizing new spectroscopic probes of metal tetrapyrroles. We are exploring the use of 1H, 13C, and 59Co NMR spectroscopy as novel probes of cobalt tetrapyrroles and cobalt tetrapyrrole-containing proteins. Cobalt tetrapyrroles catalyze a number of exciting transformations, including: methyl group transfer, radical rearrangement, dehalogenation, and hydrogen evolution.

Selected Publications

Liptak, M.D.; Fagerlund, R.D.; Ledgerwood, E.C.; Wilbanks, S.M.; Bren, K.L. “The Proapoptotic G41S Mutation to Human Cytochrome c Alters the Heme Electronic Structure and Increases the Electron Self-Exchange Rate” J. Am. Chem. Soc. 2011, 133, 1153-1155.

Liptak, M.D.; Wen, X.; Bren, K.L. “NMR and DFT Investigation of Heme Ruffling: Functional Implications for Cytochrome cJ. Am. Chem. Soc. 2010, 132, 9753-9763.

Liptak, M.D.; Fleischhacker, A.S.; Matthews, R.G.; Telser, J.; Brunold, T.C. “Spectroscopic and Computational Characterization of the Base-off Forms of Cob(II)alamin” J. Phys. Chem. B. 2009, 113, 5245-5254.

Liptak, M.D.; Datta, S.; Matthews, R.G.; Brunold, T.C. “Spectroscopic Study of the Cobalamin-Dependent Methionine Synthase in the Activation Conformation: Effects of the Y1139 Residue and S-Adenosylmethionine on the B12 Cofactor” J. Am. Chem. Soc. 2008, 130, 16374-16381.

Liptak, M.D.; Fleischhacker, A.S.; Matthews, R.G.; Brunold, T.C. “Probing the Role of the Histidine 759 Ligand in Cobalamin-Dependent Methionine Synthase” Biochemistry 2007, 46, 8024-8035.

Last modified May 04 2012 09:30 AM

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