Explore Active Areas of Research In Chemistry at Pacific

Jeannine Chan, PhD

Biochemistry: Protein Structure-Function Relationships

Dr. Chan's research interests lie in the area of protein structure - function relationships of metalloenzymes. Studies in her lab focus on the bacterial enzymes of the global nitrogen cycle, the ecology of which can have substantial impacts to both agricultural productivity and water quality. Specifically, she is investigating the mechanism of the Mo-nitrogenase, which catalyzes biological nitrogen fixation (N2 to NH3), and the biosynthesis of nitrous oxide reductase, a copper-containing enzyme which catalyzes the last step of the denitrification pathway (N2O to N2).

Recent Presentations and Publications

Chan, J. M., Bollinger, J. A., Grewell, C. L., Dooley, D. M. (2004) Reductively activated nitrous oxide reductase reacts directly with substrate. J. Am. Chem. Soc. 126, 3030-3031.

Sorlie, M., Chan, J. M., Wang, H., Seefeldt, L. C., Parker, V. D. (2003) Elucidating thermodynamic parameters for electron transfer proteins using isothermal titration calorimetry: Application to the nitrogenase Fe protein. J. Biol. Inorg. Chem. 8, 560-566.

Chan, J. M., Wu, W., Dean, D. R., and Seefeldt, L. C. (2000) Construction and characterization of a heterodimeric Fe protein: Defining roles for ATP in nitrogenase catalysis. Biochemistry 39, 7221-7228.

Christiansen, J., Chan, J. M., Seefeldt, L. C., and Dean, D. R. (2000) The role of the MoFe protein a-125Phe and beta-125Phe residues in Azotobacter vinelandii MoFe protein-Fe protein interaction. J. Inorg. Biochem. 80, 195-204.

Chan, J. M., Christiansen, J., Dean, D. R., and Seefeldt, L. C. (1999) Spectroscopic evidence for changes in the redox state of the nitrogenase P-cluster during turnover. Biochemistry 34, 5779-5785.

Chan, J. M., Ryle, M. J., and Seefeldt, L. C. (1999) Evidence that MgATP accelerates primary electron transfer in a Clostridium pasteurianum Fe protein-Azotobacter vinelandii MoFe protein nitrogenase tight complex. J. Biol. Chem. 274, 17593-17598.

 

Roxana Ciochina, PhD

Natural Products Synthesis as well as Structure - Activity Relationship (SAR) Studies of Antioxidant Agents

The main focus of our research is synthesis of natural products with interesting biological properties. Laurenditerpenol is a natural product that potentially inhibits HIF - 1, a key factor in cancer progression. We try to synthesize laurenditerpenol by using the Diels - Alder reaction in the key steps of the synthesis. Students will have the chance to explore a wide variety of organic reactions, almost all studied in their sophomore courses, with a main focus on the Diels - Alder reaction.

Our group also developed a series of curcumin derivatives and is currently looking into their antioxidant properties as well as antimicrobial, anti-inflammatory, and carcinogenic properties. Some curcumin derivatives showed a strong fluorescence and we have already started looking into their optical properties and their potential uses as fluorescent dyes in biomedical research.

 

Joel Gohdes, PhD

Inorganic Chemistry: Synthesis of Biomimetic Polymers

Students working with Dr. Gohdes are trying to develop metal containing polymers that mimic the reactivity of naturally occurring proteins and enzymes. One of our initial targets, hemocyanin, is a copper containing protein responsible for oxygen transport in mollusks. Our approach entails synthesizing copper containing molecules that are then embedded in polymers. We follow the reactivity by monitoring the UV-vis spectrum as we expose these materials to different conditions. To the right is the structure of a hydroxide-bridged, copper dimer synthesized for this project.

Recent publications 

Gohdes, J. W., Zakharov, L., Tyler, D.R., “Structure and reactivity of iron(II) complexes of a polymerizable bis-phosphine ligand”, Polyhedron,  52,  2013, 1169-1176.

Gohdes, J. W., Zakharov, L., Tyler, D.R. “trans-Bis(acetonitrile-κ N)bis{1,2-bis[bis(3-hydroxypropyl)phosphino]ethane-κ2P, P′}iron(II) dichloride” Acta Crystallogr E Struct Rep Online65(7)2009, m776-m776

Disalvo, D.; Dellinger, D.B.; and Gohdes, J.W. "Catalytic Epoxidations of Styrene Using a Manganese Functionalized Polymer" Reactive and Functional Polymers, 53(2-3), 2002, 103-112.

Recent Student Presentations 

Imitating Myoglobin with Metalated Porphyrin rings Integrated in MCM-41Moises Gonzales and Dr. Joel W. Gohdes, Murdock Conference on Undergraduate Research, Vancouver, WA, November 2021

Purifying natural gas using a polymer stabilized iron complex with alkyl phosphine ligandKeilian MacCulloch, Dr. David R. Tyler and Dr. Joel W. Gohdes, Inorganic Poster session,  257th National American Chemical Society Meeting, Orlando, Fl, March 2019

Using a Polymer Stabilized Aryl Phosphine Complex of Iron in the Purification of Natural Gas, Hoan Nguyen, Dr. David R. Tyler and Dr. Joel W. Gohdes, Inorganic Poster session,  257th National American Chemical Society Meeting, Orlando, Fl, March 2019

 Design and Synthesis of an Artificial Enzyme: A Molecular Imprinted Polymer that Mimics Zinc Containing Hydrolytic EnzymesBijoux Doherty, Dr. David R. Tyler and Dr. Joel W. Gohdes, Undergraduate Poster session,  253th National American Chemical Society Meeting, San Francisco, CA, March 2017

 Synthesis and Reactivity of Fe(TSPE)2HCl for Natural Gas PurificationBo Han, Dr. David R. Tyler and Dr. Joel W. Gohdes, Inorganic Poster session,  253th National American Chemical Society Meeting, San Francisco, CA, March 2017

 

Kevin Johnson, PhD

Physical Chemistry: Surface Chemistry Research: Spectroscopy and microscopy of liquid/solid interfaces

Students in Dr. Johnson's laboratory participate in research that investigates the molecular structure at the interface between solids and liquids. At an interface the structure of both the solid and liquid differ from that in the bulk material. The study of interfacial structure has bearing on the understanding of electrode surfaces, solid-state sensors, as well as cell surfaces in biological chemistry.

Student researchers will employ two techniques to study molecules at interfaces. Scanning tunneling microscopy (STM) and atomic force microscopy (AFM) are both scanning probe microscopy techniques that allow for the imaging of molecular structure of surfaces in situ. It is also possible to measure the molecularvibrations at interfaces using infrared reflection absorption spectroscopy (IRRAS) and surface enhanced Raman spectroscopy (SERS).

The surfaces studied are Self-Assembled Monolayers (SAMs); that is a single molecular layer on a well defined metal surface.

Recent Presentations

Kevin E. Johnson "Projects in General Chemistry Activity Sessions: Putting Theory into Practice" Presented at The 16th Biennial Conference on Chemical Education in Ann Arbor, Michigan, 31 July 2000.

Kevin E. Johnson "Electrolyte influence on lithium-ion batteries: SEI formation, damage to graphite electrodes, and the semi-empirical ethylene carbonate reduction pathway" Poster Presented at The Sigma Xi Forum and Annual Meeting in Raleigh, NC, 8-11 November 2002.

Kevin E. Johnson "Electrolyte influence on lithium-ion batteries: SEI formation, damage to graphite electrodes, and the semi-empirical ethylene carbonate reduction pathway" Poster presented at The Gordon Conference on Electrochemistry in Ventura, CA, 20-25 January 2003.

Kevin E. Johnson "Surface vibrational spectroscopy of nonaqueous electrolytes under potential control" Poster presented at The National American Chemical Society Meeting in Orlando, FL, 7-10 ASpril 2002.

Kevin E. Johnson "Implementation of model research projects in the general chemistry laboratory" Presented at The 17th Biennial Conference on Chemical Education in Bellingham, Washington, 29 July 2002.

 

Julie Layshock, PhD

Environmental & Analytical Research

Project 1: Natural pollutant remediation using wetlands

Project 2: Plasticizer migration from food packaging

Project 3: Air quality studies