Etzkorn Group
 

L to R: Back Row: Dai Nan, Alexander Rich, Jennifer Przybyla; Front Row: Xingguo Ronald Chen, Ana Y. Mercedes, Guoyan Grace Xu, Jiajia Li

 

 

Chemical Biology and Medicinal Chemistry in the Etzkorn Group

Synthetic organic templates are designed to constrain a portion of a peptide in the native conformation. The design process begins with 3D structures available for many proteins and uses chemical intuition together with molecular modeling computer programs. Synthesis efforts focus on control of stereochemistry for amino acid analogs and carbocyclic templates. Bioanalytical techniques used to characterize our mimics include: NMR, mass spectrometry, capillary electrophoresis, circular dichroism, fluorescence and X-ray crystallography.  All of our compounds are assayed for biological activity, either enzyme inhibition or DNA-binding activity.

Pin1 Inhibitors | Proline-Directed Kinases and Phosphatases | Biopolymers: Collagen Inspired Materials

| Publications | Etzkorn Group Members

Rational Drug Design: Regulation of Mitosis

We are interested several proline-directed enzymes: Pin1, a peptidyl-prolyl isomerase, Cyclin-Dependent Kinases, Scp1 and Ssu72 RNA Polymerase II phosphatases. Modern rational drug design requires the use of 3D structure-activity relationships.  We utilize X-ray crystallography and computational chemistry to design optimized inhibitors.  Combinatorial synthesis, high-throughput screening, and biological evaluation of the designed inhibitors fuels future refinements to yield potential anti-cancer drugs.

Pin1 Inhibitors (Back to Top of Page)

Figure 1. Top: Pin1 catalyzes trans-to-cis-Pro amide bond isomerization. The alkene isosteres inhibit Pin1 isomerization, and stop cancer cell growth. X-ray crystal structures of trans and cis alkene inhibitors bound in the active site of Pin1, structures by Yan Zhang and Joseph P. Noel, The Salk Institute, La Jolla, CA. (Pub. 7)

Pin1 is a key regulator of the cell cycle that may prove to be a good target for Alzheimer's disease, asthma, cancer and cocaine addiction therapeutics.  Pin1 has a significant role in regulating mitosis in cell division.  Proline-containing peptides are substrates for Pin1, a peptidyl-prolyl isomerase enzyme. We have synthesized a series of phospho-Ser-Pro mimics as inhibitors of Pin1. L-Amino acid starting materials are used to produce single diastereomeric alcohol intermediates. A Still-Wittig [2,3]-sigmatropic rearrangement is used to set the Z-alkene in the cis isostere, while an Ireland-Claisen rearrangement produces the trans isostere. The phosphoSer-trans- and cis-Pro isosteres have been incorporated into inhibitors of Pin1 that inhibit ovarian cancer cell proliferation. (Pub. 21) We are now focusing on reduced amides as transition state analogs for Pin1. (Pubs. 3, 9)  

Proline-Directed Kinases and Phosphatases (Back to Top of Page)

We are also interested in examining regulation by proline isomerization state: (1) in the cell cycle, especially of Cdk1-cyclin B and Cdc25 phosphatase, (Pub. 1), and (2) in transcription, dephosphorylation of the RNA polymerase C-terminal domain by Scp1 and Ssu72 phosphatases. (Pub. 7)

Cdk1-MS

Figure 2. Cdk1-cyclin B kinase (Cdk1) phosphorylated only the native 3, and the trans-locked Ser168-Pro isostere Cdc25c substrate, (E)-1, to give (E)-2. LC-MSMS multiple reaction monitoring (MRM) was used to measure the intensity of the peak corresponding to Cdk1-cyclin B phosphorylation sites in: (A) trans-locked (E)-1 with and without Cdk1, (B) control peptide 3, and (C) cis-locked (Z)-1, with and without Cdk1. (Pub. 1)

Biopolymers: Collagen Inspired Materials  (Back to Top of Page)

collagentrans-collagen

Figure 3. L: X-ray crystal structure (Biopolymers 2004, 76, 367) of a collagen peptide showing the three strands as: yellow ribbon, spheres and sticks. R: Same image replacing one Gly-Pro with a Gly-trans-Pro conformationally locked alkene isostere in purple. Images were created with MacPyMOL v. 0.99 (http://pymol.sourceforge.net/).

A number of medical problems arise from the breakdown or failure of collagen, including arthritis, wounds, burns, and joint damage. Collagen is the most abundant protein in the human body, and proline is the most common amino acid in collagen. We are synthesizing collagen-inspired polymers with our conformationally locked trans-Pro isosteres. (Pubs. 14, 17) The trans-proline isosteres are expected to stabilize the polymer to mimic the natural conformation of the collagen triple helix to give a biologically stable material. Standard organic synthesis techniques and a number of polymer and biopolymer characterization techniques are employed, including mass spectrometry (LC-ESI-TQ, MALDI-TOF), circular dichroism (CD), and X-ray crystallography.

Publications (Back to Top of Page)
Reverse chronological order

1.   Etzkorn FA, Zhao S, Stereospecific Phosphorylation by the Central Mitotic Kinase Cdk1-cyclin B, ACS Chem Biol, Special Issue: New Frontiers in Kinases, 2015, doi: 10.1021/cb500815b

     Our Ser-trans-Pro locked alkene isostere, but not the cis-locked, served as a peptide substrate for cyclin dependent kinase 1 (Cdk1) to demonstrate kinetic stereospecificity for the first time by a Cdk. An advanced LC-MSMS method was used to detect very low levels of the phosphopeptide products.

2.   Melin VE, Johnstone DW, Etzkorn FA, Hrubec TC, Drinking Water Treatment is Not Associated with an Observed Increase in Neural Tube Defects in Mice, Environ. Monit. Assess. 2014186, 3717-3724. doi: 10.1007/s10661-014-3652-6.

3.   Mercedes-Camacho AY, Mullins AB, Mason MD, Xu GG, Mahoney BJ, Wang X, Peng JW, Etzkorn FA Kinetic isotope effects support the twisted amide mechanism of Pin1 peptidyl-prolyl isomerase, Biochemistry 201352, 7707-7713. doi: 10.1021/bi400700b

Secondary kinetic isotope effects of labeled substrates led to a model of the twisted amide transition state. The model used our published crystal structures of Pin1 with two substrate analogues and a reduced amide transition state analogue. Highlighted in the “Top Ten Most Read Papers” banner on the Biochemistry web site during the week after publication.

4.   Park JM, Hu JH, Milshteyn A, Zhang PW, Moore CG, Park S, Datko, MC, Domingo RD, Reyes CM, Wang XJ, Etzkorn FA, Xiao B, Szumlinski KK, Kern D, Linden DJ, Worley PF A prolyl-isomerase mediates dopamine-dependent plasticity and cocaine motor sensitization, CELL 2013154, 637-650. doi: 10.1016/j.cell.2013.07.001

Our inhibitors were essential in determining the role of Pin1 in cocaine addiction.  “In terms of the Altmetric score this article has done particularly well, scoring higher than 96% of other articles ever tracked by Altmetric.” Highlighted in the news: "New insight into how brain 'learns' cocaine addiction." ScienceDaily. ScienceDaily, 1 August 2013. <www.sciencedaily.com/releases/2013/08/130801125035.htm>.

5.   Nachman, RJ, Wang, XJ, Etzkorn, FA, Kaczmarek, K, Zabrocki, J, Lopez, J, Coast, GM, Evaluation of insect CAP(2b) analogs with either an (E)-alkene, trans- or a (Z)-alkene, cis-Pro isostere identifies the Pro orientation for antidiuretic activity in the stink bug, Peptides 2012, epub:2012/10/06, doi: 10.1016/j.peptides.2012.09.026.

6.       Xu, GG, Slebodnick, C, Etzkorn, FA, Cyclohexyl ketone inhibitors of Pin1 dock in a trans-diaxial cyclohexane conformation. PLoS One. 20127, e44226, DOI:10.1371/journal.pone.0044226. PMCID: 3446931.

The Pin1 peptidyl-prolyl isomerase (PPIase) reaction is unlikely to proceed through a nucleophilic addition mechanism. Docked inhibitors adopting trans-diaxial cyclohexane conformations led us to propose a stretching mechanism for Pin1.

7.     Zhang M, Wang XJ, Chen X, Bowman ME, Luo Y, Noel JP, Ellington AD, Etzkorn FA, Zhang Y. Structural and kinetic analysis of prolyl-isomerization/phosphorylation cross-talk in the CTD code. ACS Chem Biol, 20127, 1462-1470. Epub 2012:06:05, DOI: 10.1021/cb300169c. PMCID: 3423551.

Two crystal structures of inhibitors bound to the Pin1 catalytic site are the first to demonstrate that alkene isosteres mimic amide bonds very well. RNA polymerase II C-terminal domain Ssu72 phosphatase activity was shown to be dependent upon Pin1 activity, while Scp1 phosphatase activity was not.

8.     Tarrant, MK, Rho, HS, Xie, Z, Jiang, YL, Gross, C, Culhane, JC, Yan, G, Qian, J, Ichikawa, Y, Matsuoka, T, Zachara, N, Etzkorn, FA, Hart, GW, Jeong, JS, Blackshaw, S, Zhu, H, and Cole, PA, Regulation of CK2 by phosphorylation and O-GlcNAcylation revealed by semi-synthesis. Nat Chem Biol, 2012, 8(3), 262-269. PMCID: 3288285.

9.     Xu GG, Zhang Y, Mercedes-Camacho AY, Etzkorn FA, A reduced-amide inhibitor of Pin1 binds in a conformation resembling a twisted-amide transition state. Biochemistry201150(44), 9545-9550. PMCID: 3289549.

Synthesis, bioassay, and X-ray crystal structure of a reduced amide inhibitor of Pin1 reveal a conformation that resembles a proposed twisted-amide transition state, and the roles of various Pin1 side chains in catalysis.

10.  Mercedes-Camacho, AY, and Etzkorn, FA, Enzyme-linked enzyme binding assay for Pin1 WW domain ligands, Anal Biochem, 2010,  402 (1), 77-82. doi: 10.1016/j.ab.2010.1003.1018.

A quantitative binding assay was developed to measure competition of ligands for the WW domain of Pin1 using a Pin1-HRP conjugate with no antibodies.

11.  Xu, GG; Etzkorn, FA, Convergent Synthesis of a-Ketoamide Inhibitors of Pin1. Org Lett 201012 (4), 696–699. doi: 10.1021/ol9027013

A convergent method to rapidly synthesize complex a-ketoamides was developed to for inhibitors of Pin1. Surprisingly, both diastereomeric pSer-Pro analogues were poor inhibitors of Pin1, indicating a mechanism distinct from other PPIases.

12.  Namanja AT, Wang XJ, Xu B, Mercedes-Camacho AY, Wilson KA, Etzkorn FA, Peng JW. Stereospecific gating of functional motions in Pin1. Proc Nat Acad Sci USA2011108(30), 12289-12294. PMCID: 3145719.

A conduit of residues between the catalytic and WW domains of Pin1 communicate differently depending upon whether a cis or trans alkene substrate isostere is bound.

13.  Namanja, AT, Wang, XJ, Xu, B, Mercedes-Camacho, AY, Wilson, BD, Wilson, KA, Etzkorn, FA, and Peng, JW, Toward Flexibility-Activity Relationships by NMR Spectroscopy: Dynamics of Pin1 Ligands, J Am Chem Soc2010132 (16), 5607-5609. doi:10.1021/ja9096779.

The dynamics of three of our Pin1 ligands, two of which were conformationally restricted, were measured by a new NMR method, 13C relaxation-dispersion. This method developed by Jeff Peng demonstrates flexibility-activity relationships (FAR) analogous to structure-activity relationships (SAR).

14.  Dai N, Etzkorn FA, Cis–Trans Proline Isomerization Effects on Collagen Triple-Helix Stability are Limited, J. Am. Chem. Soc., 2009, 131, 13728-13732.

By comparison with two previous alkene isosteres, a conformationally locked isostere of Pro-trans-Pro shows a small contribution of cis-trans proline isomerization in stabilizing the collagen triple-helix.

15.  Nachman RJ, Wang XJ, Etzkorn FA, Aziz OB, Davidovitch M, Kaczmarek K, Zabrocki J, Strey A, Pryor N, Altstein M, Evaluation of a PK/PBAN analog with an (E)-alkene, trans-Pro isostere identifies the Pro orientation for activity in four diverse PK/PBAN bioassays. Peptides 200930 (7), 1254-1259.

16.  Nachman RJ, Kim YJ, Wang XJ, Etzkorn FA, Kaczmarek K, Zabrocki J, Adams ME, Potent activity of a PK/PBAN analog with an (E)-alkene, trans-Pro mimic identifies the Pro orientation and core conformation during interaction with HevPBANR-C receptor. Bioorg Med Chem 200917 (12), 4216-4220.

17.  Dai N, Wang XJ, Etzkorn FA, The effect of a trans-locked Gly-Pro alkene isostere on collagen triple helix stability. J Am Chem Soc 2008130, 5396-5397.

A conformationally locked isostere of Gly-trans-Pro destabilizes a collagen-like peptide, bringing into question our understanding of collagen triple-helix formation.

18.  Zhao S, Etzkorn FA, A Phosphorylated Pro-drug for the Inhibition of Pin1. Bioorg. Med. Chem. Lett., 200717, 6615-6618.

Masking the phosphate group of an inhibitor of Pin1 with bis-(pivaloylmethoxy) groups led to improved cell permeability with an IC50 value that matched the enzyme assay an IC50 value.

19.  Liu T, Kapustin G, Etzkorn FA, Design and Synthesis of a Potent Histone Deacetylase Inhibitor, J. Med. Chem. 200750, 2003-2006.

Rational computer-based design led to a potent (Ki = 14 nM) histone-deacetylase (HDAC) inhibitor with anti-cancer drug potential that was 4.5-fold selective for HDAC1 over HDAC8.

20.  Schroeder OE, Carper E, Wind JJ, Poutsma JL, Etzkorn FA, Poutsma JC, Theoretical and Experimental Investigation of the Energetics of Cis-Trans Proline Isomerization in Peptide Models, J Phys Chem A, 2006110, 6522-6530.

The activation energetics of cis-trans proline isomerization at a series of peptide bond angles of several small proline dipeptide analogues were calculated using B3LYP/6-31+G, and the proton affinities were measured by mass spectrometry.

21.  Wang XJ, Xu B, Mullins AB, Neiler FK, Etzkorn FA, Conformationally Locked Isostere of PhosphoSer-cis-Pro Inhibits Pin1 23-Fold Better than PhosphoSer-trans-Pro Isostere, J. Am. Chem. Soc. 2004,126, 15533-15542.

We demonstrated that pSer-cis- and trans-Pro isosteres both bound to the catalytic domain of Pin1, and that the cis inhibited Pin1 ca. 20-fold more strongly than the trans isostere in both enzymatic and cell-based assays, confirming Pin1 as the target in a cancer cell line.

22.  Kapustin G, Fejér G, Gronlund JL, Seto E, McCafferty DG, Etzkorn FA, Phosphorus-Based Transition State Analogues as Histone Deacetylase Inhibitors, Org. Lett. 20035, 3053-3056.

Charged phosphonate, phosphinate, and phosphonamidate analogues of suberoyl anilide hydroxamic acid (SAHA), a known HDAC inhibitor and anti-cancer drug, did not successfully inhibit HDACs, leading to the hypothesis of a different mechanism from Zn histone deacetylases.

23.  Wang XJ, Hart SA, Xu B, Mason MD, Goodell JR, Etzkorn FA, Serine-cis- and trans-Proline Isosteres: Stereoselective Synthesis of (Z)- and (E)-Alkene Mimics by Still–Wittig and Ireland–Claisen Rearrangements, J. Org. Chem. 200368, 2343-2349.

A highly cited method for the stereoselective synthesis of cis- and trans-proline isosteres was developed in this paper.

24.  Hart SA, Trindle CO, Etzkorn FA, Solvent-Dependent Stereoselectivity in a Still-Wittig Rearrangement: an Experimental and Ab Initio Study, Org. Lett. 20013, 1789-1791.

The number of oxygen ligands around lithium in the transition state of a Still-Wittig rearrangement were found to explain the opposite stereochemical experimental outcomes in THF vs. toluene.

25.  Foulds GJ, Etzkorn FA, Protein-DNA affinities by capillary electrophoresis, In Capillary Electrophoresis of Nucleic Acids, Vol. 2; K. Mitchelson and J. Cheng, Eds.; Methods in Molecular Biology Vol. 163, Humana Press Inc.: Totowa, N.J., 2001; 369-378.

The development of experimental conditions for an innovative method for measuring protein-DNA by capillary electrophoresis are explained in detail, similar to the style of Organic Synthesis.

26.  Etzkorn FA, Travins JM, Stereospecific Labeling of prob-Protons in the NMR Structure Determination of a Helix-Turn-Helix Turn Peptidomimetic, J. Pept. Res. 200055, 436-446.

The 3-dimensional structure of a small, 12-membered-ring peptidomimetic was determined by NMR: COSY, NOESY, and J-value angle measurements, using stereospecifically labeled methylene groups.

27.  Foulds GJ, Etzkorn FA, DNA-binding affinities of MyoD and E47 homo- and hetero-dimers by capillary electrophoresis mobility shift assay (CEMSA), J. Chromatogr. A 1999, 231-236.

We used the CEMSA method developed previously to measure the DNA affinities of a different class, the helix-loop-helix DNA-binding proteins: MyoD and E47.

28.  Hart, SA, Etzkorn FA, Cyclophilin Inhibition by a (Z)-Alkene Mimic of cis-Proline, J. Org. Chem. 199964, 2998-2999.

Our first (Z)-alkene isostere of a cis-proline locked substrate inhibited human cyclophilin A with an IC50 value of 6.3 mM.

29.  Travins, JM, Etzkorn FA, Facile synthesis of D-amino acids from an L-serine-derived aziridine, Tetrahedron Lett, 199839, 9389-9392.

We developed a simple method for converting L-serine into a wide variety of unnatural D-amino acids via organocuprate opening of the aziridine.

30.  Hart, SA, Sabat, M, Etzkorn FA, Enantio- and Regio-selective Synthesis of a (Z)-Alkene cis-Proline Mimic, J Org Chem, 199863, 7580-7581.

We accomplished the first stereocontrolled synthesis of a (Z)-alkene cis-proline isostere via a Still-Wittig rearrangement.

31.  Foulds, GJ, Etzkorn FA, A capillary electrophoresis mobility shift assay for DNA-binding affinities, Nucleic Acids Res, 199826, 4304-4305.

We developed a rapid, robust, and innovative method for measuring nanomolar DNA-protein affinities by capillary electrophoresis in uncoated capillaries using laser-induced fluorescence (LIF) detection.

32.  Travins, JM, Etzkorn FA, Design and Enantioselective Synthesis of a Peptidomimetic of the Turn in the Helix-Turn-Helix DNA-Binding Protein Motif, J. Org. Chem. 199762, 8387-8393.

We designed a conformationally constrained mimic of the turn in the helix-turn-helix DNA-binding protein motif, and synthesized the desired single diastereomer via a convergent 11-step synthesis in 35 % overall yield.

33.  Etzkorn FA, Guo T, Lipton M, Goldberg S, Bartlett PA, Cyclic Hexapeptides and Chimeric Peptides as Mimics of Tendamistat, J. Am. Chem. Soc. 1994116, 10412-10425.

34.  Fejzo J, Etzkorn FA, Clubb RT, Shi Y, Walsh CT, Wagner G, The Mutant E. coli F112W Cyclophilin Binds Cyclosporin A in Nearly the Identical Conformation as Human Cyclophilin, Biochemistry 199433, 5711-5720.

35.  Etzkorn FA, Chang Z, Stolz LA, Walsh CT, Cyclophilin Residues That Affect Noncompetitive Inhibition of the Protein Serine Phosphatase Activity of Calcineurin by the Cyclophilin/Cyclosporin A Complex, Biochemistry 199433, 2380-2388.

36.  Ke H, Melrose D, Belshaw PJ, Alberg DG, Schreiber SL, Chang Z, Etzkorn FA, Ho S, Walsh CT, Crystal structures of cyclophilin A complexed with cyclosporin A or N-methyl-4-butenyl-4,4-dimethyl-threonine cyclosporin A,  Structure 19942, 33-44.

37.  Zydowsky LD, Etzkorn FA, Chang H, Ferguson, SB, Stolz LA, Ho SI, Walsh CT, Active Site Mutants of Human Cyclophilin A Separate Peptidyl-Prolyl Isomerase Activity from Cyclosporin A Binding and Calcineurin Inhibition, Protein Science 19921, 1092-1099.

38.  Benson TE, Marquardt JL, Marquardt AC, Etzkorn FA, Walsh CT, Overexpression, Purification, and Mechanistic Study of UDP-N‑acetylenolpyruvyl-glucosamine Reductase,  Biochemistry 199232, 2024-2030.

39.  Maier WF, Etzkorn FA, Hinweise zur thermodynamischen Kontrolle von relativen Hydriergeschwindigkeiten an Platin. (Indication of Thermodynamic Control in the Relative Rates of Hydrogenation on Platinum), Zeitschrift für Naturforschung 1992 47b, 175-178.

40.  McEwen AB, Etzkorn FA, Maier WF, Significance of Isotopic Distributions in Catalytic Reactions of Hydrocarbons with Dideuterium, Chimia 1987, 41, 293-297.

41.  Villani AJ, Etzkorn FA, Rotert GA, Heys JR, Synthesis of 13C, 14C and 2H13C‑Labeled Adrenoceptor Antagonists: 6‑Chloro-2,3,4,5‑tetrahydro-3‑methyl-1H‑3‑benzazepine Hydrochloride and its N‑Desmethyl Analog, J Labelled Comp Radiopharmaceuticals  198825, 1339-1347.

42.  Briggs RW, Etzkorn FA, Hinton JF, Thallium-205 Nuclear Magnetic Resonance Study of the Thallium Complex of Lasalocid (X537A), J Mag Reson 1980, 523-528.

Reviews and Commentary

1. Xu GG, Etzkorn FA, Pin1 as an anti-cancer drug target, Drug News Perspect., 2009, 22, 399-407.

      An invited and refereed review of the cancer biology and inhibitors of Pin1 to date.

2. Etzkorn FA, Pin1 Flips Alzheimer's Switch. ACS Chem. Biol. 20061, (4), 214-216.

      An invited critical commentary on a Nature paper concerning Pin1 activation of the Alzheimer’s disease inducing Ab protein.

3. Wang XJ, Etzkorn FA, Peptidyl-Prolyl Isomerase Inhibitors. Biopolymers: Peptide Science 200684,125-146.

      An invited comprehensive review of designed peptidyl-prolyl isomerase inhibitors.

4. Etzkorn FA, A phase transition for cell biology? TRENDS Microbiol.200210 (4), 200.

A book review of Cells, Gels and the Engines of Life by Gerald Pollack, Ebner & Sons, 2001.

5. Etzkorn FA, Travins JM, Hart SA, Rare Protein Turns: Helix-Turn-Helix, Gamma-Turn and cis-Proline Mimics. In Advances in Peptidomimetics; A. Abell, Ed.; JAI Press Inc.: Greenwich, CT, 1999; Vol. 2, 125-163.

A comprehensive review of mimics of three unusual protein turn mimic types.

6. Wiederrecht G, Etzkorn FA, The Immunophilins. In Immunosuppressants N.H. Sigal and M.J. Wyvratt, Eds.; Perspectives in Drug Discovery and Design; ESCOM Science Publishers, B.V.: Leiden, The Netherlands, 1994, 2, 57-84.

A comprehensive review of all the cyclophilin and FK506 Binding Protein (FKBP) enzymes, and a review of the chemical mechanism of immunophilins (peptidyl-prolyl isomerases).

7. Etzkorn FA, Stolz LA, Chang Z, Walsh CT, The role of the cyclosporin A-cyclophilin complex, FK506-FK506 binding protein and calcineurin in the inhibition of T-cell signal transduction.  Curr. Opin. Struct. Biol. 19933, 929-933.

Conference Proceedings

1.     Etzkorn, FA, Noel, JP, Zhang, Y, Wang, XJ, Pin1: Inhibitors and Mechanism. In Understanding Biology Using Peptides, Proc. 19th Am. Pept. Symp., Blondelle, S. E., Ed. Springer, Inc.: San Diego, 2006, 759-762.

2.     Hart, SA, Etzkorn, FA, (Z)-Alkene PhosphoSer-cis-Pro Substrate Analog for Pin1, a Phosphorylation-Dependent Peptidyl-Prolyl-Isomerase, Peptides for the New Millenium: Proc. 16th Am. Pept. Symp. 2000, 478-480.

3.     Bartlett, PA, Etzkorn, FA, Guo, T, Lauri, G, Liu, K, Lipton, M, Morgan, BP, Shea, GT, Shrader, WD, Waterman, S,  Intuitive- and Computer-Assisted Approaches to the Design of Conformationally Restrained Peptides and Their Mimics Proc. Robert A. Welch Found. Conf. Chem. Res., XXXV Chemistry at the Frontiers of Medicine, 1991, 45-68.

Patents

1. Travins, J. M.; Etzkorn, F. A. Peptidomimetic of Helix-Turn-Helix or Gamma-Turn, University of Virginia Patent Foundation: US, 08/978,023, 1997.

Etzkorn Group Members 

(Back to Top of Page)

(Alphabetical within categories) Please write Dr. Etzkorn <fetzkorn.at.vt.edu> to update education, employment and contact information. Join the Etzkorn Research Group on LinkedIn.

Current Members (256 Davidson Hall)

Joseph Badlato; B.S. Virginia Tech expected 2016; undergraduate research 2015 -

Sarah Parshley; B.S. Virginia Tech expected 2017; undergraduate research 2014 -

Rachelle Ware; B.S. Virginia Tech expected 2018; undergraduate research 2015 -

Former Members

Jim Anderson Ph.D.; Graduate 1998-2000; Ph.D. 2003 with Milton Brown, University of Virginia.

Ana Mercedes-Camacho Ph.D.; Graduate 2005-2011; NIH PREP Scholar 2004-2005; B.S. 2003 Universidad Metropolitana, Puerto Rico; aymerced.at.vt.edu

Shaibal Banerjee Ph.D.; post-doctoral Associate 01-06/2010; currently Assistant Professor of Chemistry Defense Institute of Advanced Technology, Pune, India; banerjeess.at.diat.ac.in

Natalie Bischoff; Undergraduate 1998, University of Virginia

Michael Bucy; Undergraduate 2002-2003; B.S. 2004; currently graduate student University of Texas Southwestern Medical School

Xingguo Ronald Chen Ph.D.; Graduate 2006-2011; B.S./M.S. 2002 Nankai University, China; <xgchen.at.vt.edu>

Benjamin Cormier; Undergraduate 2002-2003; B.S. Chemical Engineering May 2004; M.S. Chemical Engineering, Texas A&M expected in December 2005

Nan Dai; Graduate 2002-2008; B.S. 2001 Peking University, China; ndai.at.vt.edu

Tobin Dickerson; B.S. 1999 Distinguished Major; M.A. 2000 University of Virginia; Ph.D. 2004 with Kim Janda at The Scripps Research Institute (NIH Predoctoral Fellow, Eli Lilly Fellow); currently Senior Research Associate at Scripps Research Institute, Department of Chemistry, 10550 North Torrey Pines Road, BCC-582, La Jolla, CA 92037, Phone: (858) 784-2522, Fax: (858) 784-2590; tobin.at.scripps.edu

Shuang Amy Fan; Graduate student 2009 - 2014; M.S. University of Denver; M.S. Virginia Tech 2014

Andrew Fenley B.S. 2003 Virginia Tech; currently Graduate Student in Physics at Virginia Tech.

Glenn J. Foulds Ph.D., currently law student at the University of Virginia, Charlottesville, VA

Stephanie Gaillard; Undergraduate 1996, University of Virginia

Nicholas Giokas; Undergraduate 2014, B.S. expected 2017

John Goodell; REU Undergraduate 1999, University of Virginia; goodelljohn@hotmail.com

Gita Gupta; REU Undergraduate1996, University of Virginia

Allison Hager; SRIP Undergraduate 1996, University of Virginia; Currently Merck & Co. in West Point PA, Staff Biochemist in Vaccine Discovery group; allison_hager@merck.com

Charmagne Harris; REU Undergraduate 1997, University of Virginia

Scott A. Hart Ph.D. 2000 University of Virginia; 2000-2003 Yale University NIH Postdoctoral Fellow with Alanna Schepartz; Currently Development Scientist II at Amylin Pharmaceuticals, Inc.; currently Principal Scientist, Product Development at Bristol-Myers Squibb, San Diego, CA

Jennifer Hay; B.S. 2012 Virginia Tech

David Hummer; B.S. 2013 Virginia Tech

Vladimir Kalashnikov; NeoMPS, Inc., 9395 Cabot Dr., San Diego, CA 92126; vkalashnikov.at.mps-sd.com

Galina Kapustina; Postdoctoral Associate 2000-2003; Ph.D. 1989 Leningrad Institute of Chemical Technology; Postdoctoral Associate 1992-1993 Weizmann Institute; Research Scientist at Insight Pharmaceuticals, Peptor Ltd., Rehovot, Israel 1994-2000; 2003-2004 Postdoctoral Associate with Madeleine Joullie, University of Pennsylvania; currently at Provid Pharmaceuticals, Inc., Provid Pharmaceuticals Inc., 671 U.S. Route 1, North Brunswick, NJ 08902; galina.kapustin.at.providpharma.com

Vanessa Keller-Melin (Vet-Med), M.S. 2011 (co-advisor with Terry Hrubec)

Thomas Kurpiers; Visiting Graduate 2001-2002; B.S. University of Marburg, Germany; Currently Graduate Student at University of Marburg.

Michelle Lambert; Undergraduate 2001; B.S. 2003.

Jiajia Li; M.S. 2010; currently Graduate Student in Industrial Systems Engineering, Virginia Tech.

Marc Lannuzel Ph.D.; Postdoctoral Associate 2001-2003, Virginia Tech; Ph.D. 2000, University Montpellier and Pierre Fabre Research Institute, France; currently Research Chemist at Syncom BV, Groningen, The Netherlands; marc_lannuzel.at.hotmail.com

Keith Leung; Graduate 2003-2005; B.S. 2002 University of Virginia. Currently medical student at the Eastern Virginia Medical School

Julie Lim; REU Undergraduate summer 2004; University of Virginia undergraduate.

Tao Liu Ph.D.; 2002-2007; B.S./M.S. 2001 Nankai University, China; Staff Scientist, 2007-2010, American Peptide Company, 1271 Avenida Chelsea, Vista, CA 92081; currently R&D Fluids Process Chemist at Momentive Performance Materials, Parkersburg, West Virginia

Eric Lutz; REU Undergraduate 1999 University of Virginia

April Mair; REU Undergraduate 1996 University of Virginia

Kristianne Macaraeg; B.S. 2013 Virginia Tech

Kapil Malshet; Undergraduate 1998, B.S. 2001 School of Commerce, University of Virginia; kvm4z.at.alumni.virginia.edu

Susan Martin; Ph.D. 1999 with Don Hunt, University of Virginia; Currently Postdoctoral Associate at Furman University, South Carolina

Matt Mason; Undergraduate 2001, 2002-2003; B.S. 2002 Harvey Mudd College; Currently Medical Student at SUNY, Upstate Medical University; masonm@upstate.edu

David May; Undergraduate 2005-2007; B.S. expected 2007; dkmay@vt.edu

Akshitkumar Mistry; Undergraduate summer 2005; B.S. expected 2007 University of Virginia; amm9x.at.virginia.edu

Gerald Morgan; REU Undergraduate 1999, University of Virginia

Ashley Mullens; Graduate 2003-2005; B.S. 2002 in Biology, Virginia Tech; currently at Luna Innovations; asmullin.at.vt.edu

Elizabeth Niehaus; Undergraduate 1999, University of Virginia; Linguistics major; Studied in Spain 2000-2001; ekn5b.at.virginia.edu

Freda Katie Neiler; B.S. 2003, Virginia Tech; Currently 2008 PharmD Candidate, Virginia Commonwealth University/Medical College of Virginia School of Pharmacy; neilerfk@vcu.edu

Boobalan Pachaiyappan; M.S. 2005; B.S. University of Madras; M.S. 2003 Indian Institute of Technology, Bombay; boobalan.at.vt.edu

Jared Peak; B.S. 2003 in Biochemistry, Virginia Tech; currently Scientist II with GlaxoSmithKline.

Amanda Pester; Graduate 2012 – 2014

Jennifer Przybyla; Graduate 2006-2009; B.S. 2003, Indiana University; M.S. 2006 Southeast Missouri State University, przybyla.at.vt.edu; currently Graduate Teaching Assistant at Oregon State University, Corvallis, OR

Pardha Pyla; Computer Science Graduate 2001-2002; pardha.at.vt.edu; currently User Experience Lead for Mobile Platforms at Bloomberg LP, Greater New York City Area

Nikki Reyer; Undergraduate 1997, University of Virginia

Alex Rich; Undergraduate B.S. 2009 Virginia Tech

Melinda Richardson; Undergraduate 2001, B.S. 2002 Virginia Tech, Currently Pharmacist's Assistant at Krogers; merichar.at.vt.edu

Daniel Shields; Undergraduate B.S. 2013 Virginia Tech; undergraduate research 2012 - 2013

David Shonka M.D.; Undergraduate B.S. 2000 Distinguished Major, University of Virginia; Currently University of Virginia Medical School; dcs5z.at.virginia.edu

Matthew Shoulders Ph.D.; Undergraduate 2003-2004; B.S. 2004 Virginia Tech; Ph.D. from U. Wisconsin, Madison; Currently Assistant Professor of Chemistry at MIT.

Sarah Snader; Undergraduate, B.S. Virginia Tech expected 2016; undergraduate research 2014 - present

Jennifer Stockdill Ph.D.; Undergraduate 2001-2002; B.S. 2003, Virginia Tech; Ph.D. from Cal Tech; Currently Assistant Professor of Chemistry at Wayne State University.

Keith Sutyak; B.S. Biochemistry 2011 Virginia Tech; undergraduate research Fall 2013.

Lucy Tamberino; B.S. 2013 Virginia Tech; undergraduate research

Jeremy M. Travins Ph.D.; 1999, University of Virginia; Postdoctoral Associate 1999-2001 with Dan Rich, University of Wisconsin, Madison, WI; Scientist Medicinal Chemistry at Johnson & Johnson Pharmaceutical Research and Development, Spring House, PA; Currently jtravins.at.prdus.jnj.com

Lucas Tucker; Undergraduate 2006

Xiaodong Jane Wang Ph.D.; Graduate 2000-2005, Ph.D. 2005; B.S. Nankai University, China; 2005-2006 Postdoctoral Associate with Laurence Hurley at the University of Arizona, Tucson, AZ; 2006-present Staff Scientist Sanofi-Aventis, Phoenix, AZ.

Luke Wiseman Ph.D.; Undergraduate 2000, B.S. 2000 University of Virginia; Ph.D. 2005 with Jeffrey Kelly at Scripps Research Institute; Postdoctoral Associate with David Ron at The Skirball Institute, New York University School of Medicine, NY; Currently Research Professor of Chemistry at Scripps Research Institute

Jian Wu M.S. 2010 Virginia Tech; Currently graduate student in Food Science, Virginia Tech

Guoyan Grace Xu Ph.D.; Graduate 2004-2011; B.S./M.S. 2003 Nankai University, China; Currently Post-doctoral Associate at Virginia Commonwealth University; guxu1.at.vt.edu

Anita Yang; Undergraduate; B.S. expected 2016

Loretta Yang; Undergraduate; B.S. 1997 Distinguished Major, University of Virginia; Ph.D. 2005 with Alanna Schepartz in Molecular Biophysics and Biochemistry at Yale University

Virginia Yo; Undergraduate 1993, University of Virginia

Song Zhao Ph.D.; Graduate 2003-2007; B.S./M.S. 2002 East China University of Science of Technology, China; sozhao.at.vt.edu; currently Scientist at PPD, Richmond, VA