Dr. Suara Adediran Publishes Paper in Biochimica et Biophysica Acta (BBA) – Proteins and Proteomics

Dr. Adediran and co-authors Michael J. Morrison and R.F. Pratt have published a paper in Biochimica et Biophysica Acta (BBA) – Proteins and Proteomics. The title is “Detection of an Enzyme Isomechamism by Means of the Kinetics of Covalent Inhibition.”

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Abstract

Turnover of substrates by many enzymes involves free enzyme forms that differ from the stable form of the enzyme in the absence of substrate. These enzyme species, known as isoforms, have, in general, different physical and chemical properties than the native enzymes. They usually occur only in small concentrations under steady state turnover conditions and thus are difficult to detect. We show in this paper that in one particular case of an enzyme (a class C β-lactamase) with specific substrates (cephalosporins) the presence of an enzyme isoform (E′) can be detected by means of its different reactivity than the native enzyme (E) with a class of covalent inhibitors (phosphonate monoesters). Generation of E′ from E arises either directly from substrate turnover or by way of a branched path from an acyl-enzyme intermediate. The relatively slow spontaneous restoration of E from E′ is accelerated by certain small molecules in solution, for example cyclic amines such as imidazole and salts such as sodium chloride. Solvent deuterium kinetic isotope effects and the effect of methanol on cephalosporin turnover showed that for both E and E′, kcat is limited by deacylation of an acyl-enzyme intermediate rather than by enzyme isomerization.

The full text of the paper can be found at: https://www.sciencedirect.com/science/article/abs/pii/S157096392100087X

 

 

Dr. Colin Smith Receives NIH Grant

Colin Smith, Professor of Chemistry

The Smith Lab studies protein structure and dynamics using a combination of computer simulation and nuclear magnetic resonance (NMR) spectroscopy. They are particularly interested in optimizing the dynamics of computationally designed proteins and understanding how mutations allosterically affect the functions of natural proteins.

To advance the understanding of atomic-level mechanisms behind critical protein functions like enzyme catalysis and allosteric regulation, it is important to first elucidate a true representation of the protein in solution. In an effort to achieve this long term goal, Dr. Smith will use the recently developed Kinetic Ensemble approach to transform the way in which nuclear magnetic resonance (NMR) data is computationally modeled to solve protein structures and measure protein motions. NMR is one of the most powerful techniques for elucidating the structure and dynamics of proteins. It enables their study in solution (unlike X-ray crystallography) and can capture critical structural rearrangements as they happen at room temperature (unlike cryo-electron microscopy). However, despite these advantages, there have been relatively few practical improvements to one of the foundational aspects behind the way protein structures are solved, namely the calculation of interatomic distances from nuclear Overhauser effect (NOE) experiments. Such methods have remained largely qualitative, resulting in large uncertainties in the atomic positions for most NMR structures. Also, the field has almost completely ignored how angular motion and kinetics affect the NOE, resulting in atoms appearing much further away from one another than they actually are. To overcome these significant deficiencies, Dr. Smith and his team will implement and test new Kinetic Ensemble-based refinement algorithms that are considerably more accurate and physically realistic than previous approaches, accounting for both angular motion and kinetics. To eliminate a significant fraction of the systematic and random structural errors resulting from poorly quantified NMR spectra, they will also integrate advances made by the FitNMR peak quantification software recently developed by their lab. These methods will be used to create better experimental NMR structures, more exhaustive models of side chain dynamics, and determine differences between solution and crystal states with unprecedented detail. This work will allow much more accurate determination of the structural dynamics in parts of the protein exhibiting significant fluctuations, including protein active sites, regulatory regions, and hidden binding sites. Such knowledge will advance our fundamental understanding of protein biophysics and facilitate rational design of new therapeutics.

Funding for this R15 Grant is provided by National Institute of General Medical Sciences (NIGMS).

Dr. Brian Northrop Receives NSF Grant

Northrop’s proposal, titled “Phenazine chemistry as a means of assembling multifunctional π-conjugated organic materials” is motivated by the desire to understand how the structure, functionality, and dimensionality of π-conjugated organic materials impacts their physical, optical, redox, and electronic properties. Toward this fundamental goal he and his students will use the condensation reactions between ortho-phenylenediamine derivatives with ortho-quinone compounds to prepare multifunctional phenazine derivatives. Phenazines are example N-heteroacenes that, similar to their hydrocarbon acene analogues, exhibit desirable electronic and optoelectronic properties. Phenazines, however, are more stable, better electron acceptors (n-type materials), and more synthetically modular. The majority of phenazine derivatives synthesized to date have been linearly functionalized azaacenes while very few examples of organic materials combining phenazine and other π-conjugated functionalities are known. Developing a thorough understanding of phenazine assembly and integration into multifunctional molecules will lead to entirely new classes of organic electronic materials and significantly advance our ability to investigate fundamental relationships between size, functionality, lattice topology, and dimensionality on the properties of π-conjugated materials. The principle objectives of the proposed research are to: (1) combine experimental synthesis and first principles calculations to investigate the formation and aromaticity of simple phenazine derivatives as well as the impact of functional groups on the favorability and reversibility of phenazine condensation reactions; (2) synthesize a library of o-phenylenediamine and o-quinone functionalized building blocks that will be used in the controlled assembly of one-dimensional multifunctional phenazine derivatives and oligomers; (3) apply new knowledge from fundamental and one-dimensional phenazine studies to prepare monodisperse, two-dimensional phenazine ladders and grids. The phenazine-based multifunctional materials are expected to have unique semiconducting and optoelectronic properties with potential applications as organic field-effect transistors, photovoltaics, light-emitting diodes, and sensors.

Fire & Ice Event 2021

On May 4th, the Chemistry Majors’ group, the Free Radicals, held the annual Fire and Ice Event on the patio of the Exley Science Center. Students performed a number of chemical demonstrations and entertained fellow students, faculty, and staff with lighthearted one-liners.  Among the experiments performed, students blew up several balloons with various gas concentrations, created a flaming tornado inside two shields, burned a quantity of magnesium inside a solid block of dry ice, ignited thermite within a clay pot, and blew up guncotton (nitrocellulose).

Student demonstrations were performed by: Emily Aoki, Gianna Argento, California Clark, Oliver Cho, Bryan Guarin, Sterre Hesseling, Dylan Judd, and Kyle Sylvester.

Click here for a short video from the event.

 

2021 Annual Chemistry Department Awards

Awards – ACS Younger Chemists Committee

The Chemistry Department is proud to announce the recipients of the 2021 Annual Chemistry Department Awards:

ACS Analytical Award: Cole Harris
Awarded for excellence in analytical chemistry
ACS Award in Inorganic Chemistry: Abrar Habib
To recognize achievement in inorganic chemistry and to encourage further study in the field
ACS Award in Organic Chemistry: Niels Vizgan
To a student who has displayed a significant aptitude for organic chemistry
ACS Award in Physical Chemistry: Caitlin Grant
To recognize achievement in physical chemistry and to encourage further study in the field
ACS Connecticut Valley Section Award: Emma Shapiro
For outstanding achievement by a graduating chemistry major
American Institute for Chemists Award: Gianna Argento
For outstanding achievement by a graduating chemistry major
Bradley Prize: Sterre Hesseling & Emma Shapiro
To the senior or junior who excels in chemistry and particularly in special original work
Silverman Prize: Oliver Cho & Annika Velez
Awarded to a member of the junior or senior class for excellence in chemistry
Peirce Prize: Sophia Marra
Awarded for excellence in chemistry
CRC Award (General Chemistry): Alexis Papavasiliou 

For the outstanding first-year student in Principles of Chemistry
CRC Award (Organic Chemistry): Anne Kiely
For the outstanding first-year student in Organic Chemistry
Hawk Prize: Kate Luo
To the students who have done the most effective work in biochemistry
Martius Yellow Award: Sophie Wazlowski
Awarded for excellence in Integrated Chemistry Laboratory
The Wallace C. Pringle Prize for Research in Chemistry: Sean McDarby
Awarded to a student for excellence in research
Peterson Fellowship: Nick Wells
For graduate study in biochemistry
Tishler Prize: Jeff Keyes
Awarded to the best graduate teaching assistant in chemistry

Vasileios Drogkaris Receives PhD


Dr. Vasileios Drogkaris

Dr. Vasileios Drogkaris successfully defended his Ph.D. thesis titled “Exploring the self-assembly of conjugated materials and the utility of the thiol-Michael reaction in macromolecular synthesis” on March 2nd, 2021. Vasili came to Wesleyan in 2014 after receiving his B.S. in chemistry from the University of Athens, Greece. While an undergraduate Vasili carried out research investigating ring-opening metathesis polymerization techniques using novel tungsten catalysts. At Wesleyan, Vasili joined the lab of Prof. Northrop and embarked on several research projects exploring the dynamic covalent self-assembly of boronic acids as well as the use of thiol-Michael reactions in macromolecular synthesis. Most prominently, Vasili developed the dynamic self-assembly of a series of boronate ester-bridged oligo(phenylene ethynylene) ladder compounds that have laid the groundwork for increasing our understanding of π-conjugation in one-dimensional versus two-dimensional materials. Vasili has recently accepted a position at Spartech, a leader in specialty plastics and packaging.

 

Dr. Michelle Personick Conferred Tenure

It is with great pleasure that the Chemistry Department announces the promotion of Dr. Michelle Personick, who was conferred tenure by the Board of Trustees at its most recent meeting. In the summer of 2015, Michelle joined the faculty at Wesleyan University as an assistant professor of chemistry, where her independent research program continues to include an assortment of colorful noble metals. Dr. Personick’s research in inorganic chemistry is focused on developing tailored metal nanoparticles that function as improved catalysts for energy- and resource-efficient chemical synthesis and the clean production of energy. Her goal is to transform the overall energy landscape and offset the driving forces of climate change. She has published numerous peer-reviewed articles and one book chapter, and her work has been supported by grants from the National Science Foundation, Army Research Office, and American Chemical Society Petroleum Research Fund. Professor Personick offers courses on Principles of Chemistry II, Advanced Inorganic Chemistry, Chemistry of Materials and Nanomaterials, and Nanomaterials Laboratory. Join us in celebrating this momentous achievement!

 

Michelle Personick, Associate Professor of Chemistry

 

Dr. Carla Coste Sánchez Joins the Chemistry Department

 

 

The Chemistry Department is pleased to welcome Dr. Carla Coste Sánchez as a Visiting Assistant Professor of Chemistry. Professor Coste Sánchez holds a Chemistry degree from the University of Puerto Rico and a Ph.D. in Pharmaceutical Sciences from the University of North Carolina – Chapel Hill. Her graduate work focused on developing an orally available chelating agent for decorporation of different metals. Afterwards, she completed a year-long postdoc in the Center for Innovative Pharmacy Education (CIPhER) at UNC-CH. Her interests include science education, pharmaceutics, and drug delivery. In her down time, she enjoys hiking, camping, and various crafts like quilting.  The department is delighted to have her join us!

 

 

 

Chemistry Major Elected to Phi Beta Kappa

Fall 2020 elections to Wesleyan’s Gamma Chapter of Phi Beta Kappa have been announced, and it is with great pleasure that we recognize Kate Yuru Luo.

To be elected, a student must first have been nominated by the department of his or her major. The student also must have demonstrated curricular breadth by having met the General

Education Expectations and must have achieved a GPA of 93 or above.

The emblem contains the three Greek letters “Phi,” “Beta,” and “Kappa,” which are the initials of the Greek motto, Philosophia Biou Kybernetes, or “the love of wisdom is the guide of life.”

Kate Yuru Luo, 2021
Chemistry, Neuroscience & Behavior Program

Elected students will be honored at an induction ceremony on zoom, which you are welcome to join on Wednesday, December 2, 2020 at 4:30p.m. https://wesleyan.zoom.us/j/97430798751?pwd=ckQ5anhRTjhtRjRVekhCZytnc3c0UT09

Meeting ID: 974 3079 8751
Passcode: 599665