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Meet Heather Pigram!

Heather PigramI was born in Louisville second oldest of four.  During high school I thought music was going to be my life until college.  I attended UofL but soon transferred to UK where I found what I enjoyed.  I received a Bachelor’s Degree of Hospitality and Management Tourism.  Working as a front desk for Holiday Inn Express in Nicholasville wasn’t my ideal job.  Friends encouraged me to apply at UK.  A week later I got a phone call asking me to come in the next day to start work.  I began working with the A&S IBU for Chemistry, Physics, and Anthropology through STEPS. I worked for about two months as a STEPS employee before I became a permanent full-time employee in January.

1. What do you do in your spare time? 

During my spare time I enjoy reading ScFi, mystery, and adventure, shopping, watching NFL, going out with friends and playing my clarinet.

2. What is your favorite movie or book?

My favorite book is Huckleberry Finn by Mark Twain.  My favorite movie is The Wizard of Oz.

3. What is one ambition or goal you have for the next year? 

40th Annual Naff Symposium

 

8:00 a.m. Registration & Continental Breakfast 

Gallery, W.T. Young Library
8:45 a.m. Welcome

Dr. Eli Capilouto, University of Kentucky President

Auditorium, W.T. Young Library
9:00 a.m. Dr. Hao Yan  

Designer Architectures for Programmable Self-assembly

Auditorium, W.T. Young Library
10:00 a.m. Break (refreshments available)

Gallery, W.T. Young Library
10:30 a.m. Dr. Donald Ingber

From Cellular Mechanotransduction to Biologically Inspired Engineering

Auditorium, W.T. Young Library
11:30 a.m. Lunch
1:30 p.m. Poster Session

King Alumni House Ballroom
2:30 p.m. Dr. Todd Yeates

Giant Protein Cages and Assemblies in Nature and by Design

Auditorium, W.T. Young Library

 

More information about this annual event can be found here.

Faculty Host: Dr. Jason DeRouchey

 

Date:
-
Location:
William T. Young Library

Chemistry Department Seminar

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Deepshikha Gupta of the UK Chemistry Department will be presenting a seminar titled:

1) New Approaches to Cyclopentadienyl-Fused Thiophene Complexes of Iron 

2) Carbonic Anhydrase Active-Site Mimics for CO2 Hydration

Topic 1 - New Approaches to Cyclopentadienyl-Fused Thiophene Complexes of Iron
 
Abstract: One fundamental property that normally distinguishes polymers from metals is their electrical conductivity. The value of electrical conductivity for metals is very high. During the last two decades, researchers, through the simple modification of ordinary organic conjugated polymers, have succeeded in preparing electrically conducting polymers. These materials combine the electrical properties of metals with the advantages of polymers, such as lighter weight, greater workability, resistance to corrosion and chemical attack and lower cost. These properties make them extremely attractive for many applications, including light-emitting diodes (LEDs), chemical and biological sensors, microelectronic devices, and advanced textiles. Our group’s long-term interest is in the electronic properties of organometallic analogues of the low-band-gap polymer poly(benzo[3,4-c]thiophene) (polyisothianaphthene) that incorporates η5-cyclopenta[c]thienyl monomers such as ferroceno[c]thiophene. In this talk, synthetic routes to 1,4-dihydro-2,3-ferrocenodithiin, an important precursor of ferroceno[c]thiophene will be discussed. 
 
Topic 2 - Carbonic Anhydrase Active-Site Mimics for CO2 Hydration
 
Abstract: The enhancement of CO2 absorption using a catalyst is a critical component to reduce the capital cost for CO2 capture. Our research focuses on exploring effective ways to minimize CO2 emission by developing a catalyst to enhance the rate of CO2 hydration. We focus our efforts on complexes of zinc(II) and similar metal ions with ligands such as 1,4,7,10-tetraazacyclododecane (cyclen), 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane (teta and tetb), tris(benzimidazolylmethyl)amine (BIMA) and anionic tris(pyrazolylborate)s that mimic the enzyme, carbonic anhydrase. Several of these complexes reported so far contain the hazardous perchlorate ion. We are developing Cu, Co and Zn complexes with benign, non-coordinating counterions that avoid the potentially explosive perchlorate salts. [Zn(cyclen)H2O][SiF6] as well as a number of other catalysts have been synthesized and tested for their post-combustion CO2 capture enhancement capabilities in aqueous solvent mixtures. [Zn(cyclen)(H2O)][SiF6]•2H2O, which has an unreactive counteranion, has confirmed catalytic activity. 
 

Faculty Advisor: Dr. John Selegue

 

Date:
-
Location:
CP-137

Chemistry Department Seminar

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Warintra "Ning" Pitsawong of the UK Chemistry Department will be presenting a seminar titled:

Fundamental elements of the catalytic mechanism of Nitroreductase, a promiscuous enzyme

Abstract: The oxygen-insensitive nitroreductase from Enterobacter cloacae (NR) catalyzes two-electron reduction of nitroaromatics to the corresponding nitroso compounds and, subsequently, to hydroxylamine products. NR has an unusually broad substrate repertoire, which may be related to protein dynamics (flexibility) and/or a simple non-selective kinetic mechanism. To investigate the possible role of mechanism in NR's broad substrate repertoire, the kinetics of oxidation of NR by para-nitrobenzoic acid (p-NBA) were investigated using stopped-flow techniques at 4°C.  The results revealed a hyperbolic dependence on the p-NBA concentration with a limiting rate of 1.9 ± 0.1 s-1, indicating one-step binding prior to the flavin oxidation step. There is no evidence for a distinct binding step in which specificity might be enforced. The reduction of p-NBA is rate-limiting in steady-state turnover (1.7 ± 0.3 s-1). The pre-steady-state reduction kinetics of NR by NADH indicate that NADH reduces the enzyme with a rate constant of 700 ± 20 s-1 and a dissociation constant of 0.51 ± 0.04 mM.  Thus we demonstrate simple transient kinetics in both the reductive and oxidative half-reactions that help to explain NR's broad substrate repertoire.

The mechanism for nitroaromatic reduction by nitroreductase requires the transfer of two electrons and two protons overall. Electrons transfer from reduced anionic FMN, which is the cofactor of NR.  One proton has been proposed to be transferred from reduced flavin (as part of hydride transfer) or transferred as a proton from solvent in electron-coupled proton transfer. The other proton must be transferred from solvent. To gain insight into the sources of protons participating in nitroaromatic reduction, X-ray crystallography has been combined with measurement of the primary and solvent kinetic isotope effects (KIEs). The transient kinetics revealed that a large primary KIE of 3.2 ± 0.2 applies to flavin reduction by NADH (reductive half-reaction) suggesting hydride transfer directly from NADH to the flavin N(5). Moreover, a primary KIE of 1.5 ± 0.05 applies to the turnover number, indicating hydride transfer from N(5) atom to p-NBA (oxidative half-reaction). The measured solvent KIEs are consistent with solvent as the source of the second proton.  Thus we have been able to characterize electron transfer events via the optical signatures of the different oxidation states of the flavin, and proton transfer steps via KIE to document the fundamental steps that make up the catalized chemical reactions of NR.

Faculty Advisor: Dr. Anne-Frances Miller

 

Date:
-
Location:
CP-137
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