Kilbey’s Research Leadership with ORE

October 22, 2020 by Kayla Benson

Mike Kilbey wraps up a year of research leadership at the UT, Knoxville, serving as chair of the Research Council of Faculty Senate and as a Faculty Fellow for Strategic Research Initiatives in the Office of Research and Engagement.

The Research Council works to promote excellence in research, scholarship, and creative activity, and provides counsel to the university’s research administration on matters that effect research.

The role of a Faculty Fellow is to assist the Associate Vice Chancellor for Strategic Research Initiatives and their team in efforts to strategically position and enhance competitiveness for large, multidisciplinary research funding.

“It was exciting to see the diversity of scholarly work that is ongoing at UT, to connect with faculty and research leaders from across the university, and to be engaged at a time when dynamic changes that impact the research landscape of the university are taking place,” Kilbey said.

Heberle Lab’s Latest Achievements

October 21, 2020 by Kayla Benson

Research in the Heberle Lab is aimed at elucidating the structure and function of biological membranes, with a focus on the plasma membrane.

Fred A. Heberle is coauthor of the recently published book Characterization of Biological Membranes. This book explores the high importance  of membranes in the fields of biology, pharmaceutical chemistry and medicine, since much of what happens in a cell or in a virus involves biological membranes. This book is an excellent introduction to the area, which explains how modern analytical methods can be applied to study biological membranes and membrane proteins and the bioprocesses they are involved to.

Heberle was also awarded $1.7M from the National Institutes of Health (NIH) for The Research Project (R01). The R01 is the original and historically oldest grant mechanism used by NIH. The R01 provides support for health-related research and development based on the mission of the NIH. The Heberle Lab aims to extend membrane studies through an unprecedented integration of lipidomics, biophysical experiments, cryogenic transmission electron microscopy (cryoEM), and advanced molecular simulations, to test their central hypothesis that compositionally asymmetric membranes have unique biophysical properties resulting from robust coupling between lateral and transverse membrane organization. 

The Heberle Lab had a journal cover on Nanoscale for their work on “Transverse lipid organization dictates bending fluctuations in model plasma membranes.” 

The Heberle Lab published their research “Direct label-free imaging of nanodomains in biomimetic and biological membranes by cryogenic electron microscopy” in Proceedings of the National Academy of Sciences of the USA. They worked with a collaborative team to capture the first direct images of tiny cell membrane domains known as lipid rafts. The images were published as a journal cover in PNAS. 

PNAS also published the Heberle Lab’s collaborative research “How cholesterol stiffens unsaturated lipid membranes.”  Their observations that cholesterol causes local stiffening in DOPC membranes indicate that a reassessment of existing concepts is necessary. These findings have far-reaching implications in understanding cholesterol’s role in biology and its applications in bioengineering and drug design.

Xue Group’s Recent Research

October 21, 2020 by Kayla Benson

The Xue group has published multiple papers this year. This group’s research focuses on three areas: spectroscopic studies of molecular magnetism, synthesis and characterization of transition metal complexes, and the development of new chemical analyses. 

 Inorganic Chemistry published their work “Inter-Kramers Transitions and Spin–Phonon Couplings in a Lanthanide-Based Single-Molecule Magnet.” Spin–phonon coupling plays a critical role in magnetic relaxation in single-molecule magnets (SMMs) and molecular qubits. This research shows spin–phonon couplings between IR-active phonons in a lanthanide molecular complex and Kramers doublets (from the crystal field). This study unveils and measures the spin–phonon couplings in a typical lanthanide complex and throw light on the origin of the spin–phonon entanglement.

Chinese Journal of Inorganic Chemistry published the group’s work on “Direct Observation of Magnetic Transitions in a Nickel(II) Complex with Large Anisotropy.” 

Chemosphere published their work “Sustained Release of Persulfate from Inert Inorganic Materials for Groundwater Remediation.” This work demonstrates the potential feasibility of sustained persulfate release from inert matrices for groundwater treatment.

They also have an invited review for the Comprehensive Coordination III  on Tantalum in press. 

Vogiatzis Lab Published in Physical Chemistry Letters

September 10, 2020 by Kayla Benson

The Vogiatzis Lab published their work “Direct Identification of Mixed-Metal Centers in Metal−Organic Frameworks: Cu3(BTC)2 Transmetalated with Rh2+ Ions” in a collaborative piece in The Journal of Physical Chemistry Letters.

Raman spectroscopy was used to establish direct evidence of heterometallic metal centers in a metal–organic framework (MOF). The Cu₃(BTC)₂ MOF HKUST-1 (BTC^3– = benzenetricarboxylate) was transmetalated by heating it in a solution of RhCl₃ to substitute Rh²⁺ ions for Cu²⁺ ions in the dinuclear paddlewheel nodes of the framework. In addition to the Cu–Cu and Rh–Rh stretching modes, Raman spectra of (Cu_xRh_1–x)₃(BTC)₂ show the Cu–Rh stretching mode, indicating that mixed-metal Cu–Rh nodes are formed after transmetalation.

Density functional theory studies confirmed the assignment of a Raman peak at 285 cm^–1 to the Cu–Rh stretching vibration. Electron paramagnetic resonance spectroscopy experiments further supported the conclusion that Rh²⁺ ions are substituted into the paddlewheel nodes of Cu₃(BTC)₂ to form an isostructural heterometallic MOF, and electron microscopy studies showed that Rh and Cu are homogeneously distributed in (Cu_xRh_1–x)₃(BTC)₂ on the nanoscale.

Do Lab Published in Analytical Chemistry

September 4, 2020 by Kayla Benson

The Do Lab published their research “Cytotoxicity of α-Helical, Staphylococcus aureus PSMα3 Investigated by Post-Ion-Mobility Dissociation Mass Spectrometry” in Analytical Chemistry.

Staphylococcus aureus, a major bacterial human pathogen, secretes phenol-soluble modulin (PSM) peptides to stimulate inflammatory responses and kill human cells. PSMα3 is the prominent member of the PSM family and exerts its toxic function via the formation of cross-α fibrils. The fibril structure of PSMα3 resembles the eukaryotic amyloid fibrils found in the brain of Alzheimer’s disease patient, but each unit is an α-helix peptide and not a β-strand.

In this study, the Do Lab investigated how oligomeric structures and interactions with cell membrane mimetics could determine peptide cytotoxicity. To overcome the dynamic nature of interaction and aggregation process, they use ion mobility spectrometry mass spectrometry (IMS-MS) to measure the molecular shapes of the oligomeric species.

Due to the weakly-bound nature of these oligomers, it is possible for them to dissociate within the mass spectrometer. This phenomenon, called post-ion mobility dissociation, has been well documented in the past but has not been considered in previous biomolecular self-assembly studies.

The Do Lab took advantage of this typically undesired phenomenon to elucidate the molecular structures of the oligomers and determine the number of detergent molecules (which mimic the lipids in cell membrane) required to stabilize the complexes.

Consequently, the most toxic PSMα3 variant was shown to preserve its α-helical signature and required the smallest number of detergent molecules, indicating that a key virulence factor of toxic PSMα3 lies in its ability to quickly insert into the cell membrane. The same approach can be applied to similar peptide systems. Amber Gray, first author and graduate student said, “Ultimately, our study highlights the ambiguity previously present in IMS-MS data and sheds new insight into the interpretation of such data in biomolecular self-assembly studies.”

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Welcome New Department Members

August 24, 2020 by Kayla Benson

Viktor Nemykin, Department Head

Nemykin received his BS and MS in chemistry from the Kyiv State University and a PhD from the National Academy of Sciences in Ukraine working on transition-metal and lanthanide phthalocyanines. He received a highly competitive postdoctoral fellowship, supported by Japan Society for the Promotion of Science, which he completed at Tohoku University working on the preparation of phthalocyanines and their analogs. After completing another postdoctoral program at Duquesne University in bio-inorganic chemistry, Nemykin joined the faculty of the Department of Chemistry and Biochemistry at the University of Minnesota Duluth. In 2016, Nemykin was recruited as a department head to the University of Manitoba. He joined the UT chemistry department in August 2020.

 

Joshua Baccile, Assistant Professor

The focus of Baccile’s doctoral research applied analytical chemistry approaches for a comprehensive annotation of cryptic biosynthetic gene clusters (BGCs) in filamentous fungi. Central to his efforts was the use of 2D-NMR and HPLC-MS-based comparative metabolomics. Correlating changes in fungal metabolomes with genetic modification of BGCs enabled the synchronous discovery of new chemical species and enzymatic activity. His team expanded the recently emerging class of natural products, fungal isoquinolines, to include the imizoquins from the imq cluster in the plant pathogenic fungus Aspergillus flavus. Beyond detailing imq biogenesis, they discovered a functional basis for the imizoquins through characterizing antagonistic cross-talk with the ralstonins of the bacterium Ralstonia solanacearum. While thousands of natural products have been described, their functions within the producing organisms are largely unknown. Baccile’s efforts to bridge this gap, such as his study of the imizoquins, will be important for sustained agriculture, biotechnology, and drug discovery.

 

Ashleigh Thomas, Lecturer

Originally from Beckley, West Virginia and earned a PhD at UT in 2011. Thomas served as an Assistant Professor of Chemistry at Lincoln Memorial University from 2011 until 2020. This fall, Thomas will be teaching CHEM260, CHEM269, and CHEM389. 

 

Douglas Stuart, Lecturer

Originally from State College, Pennsylvania and earned a PhD at Indiana University, Bloomington with Shuming Nie. Stuart performed postdoctoral research with RP Van Duyne at Northwestern University exploring biological applications of the optical properties of noble metal and semiconductor nanoparticles. This fall, Stuart will be teaching CHEM130, CHEM339, and CHEM379.

Diversity & Inclusion

August 17, 2020 by Kayla Benson

Mourning the Passing of Ffrancon Williams

July 25, 2020 by Kayla Benson

Thomas Ffrancon Williams was born on January 30, 1928, and passed away on July 18, 2020.

Williams received his BSc degree from University College London in 1949, and an external Ph.D. degree from the University of London in 1960. He was employed at the Atomic Energy Research Establishment, Harwell, United Kingdom from 1949 to 1961 except for a leave of absence as a research and teaching associate at Northwestern University from 1957 to 1959. In 1961 he joined the chemistry faculty at the University of Tennessee, Knoxville.

“Francon was a dedicated teacher and outstanding experimental physical chemist,” said Jeffery Kovac, chemistry emeritus professor. “He was an ESR spectroscopist who studied radicals produced by gamma radiation.  Ffrancon did some groundbreaking work on cationic polymerization,” 

Williams was a National Science Foundation Visiting Scientist to Kyoto University, Japan from 1965 to 1966 and was the recipient of a Guggenheim Fellowship in 1972. He has been chairman of the Gordon Research Conferences on Radiation Chemistry (1971) and Radical Ions (1984), and served as an associate and consultant editor of Radiation Research, the official journal of the Radiation Research Society, from 1994 to 1999.

“He was always so kind and nice to me. Our respect went both ways. I will surely miss him, his kind words and phone calls,” said Pam Roach, chemistry staff.

“Ffrancon was a devoted member of our chemistry faculty for many years, and had a wonderful, calm and knowledgeable manner about him,” said Don Esidenberg, development director. “He will surely be missed. Gratefully, he will be remembered by future generations through the Ffrancon Williams Faculty Award in Chemistry Endowment.”