Members of the Erie Group focus on using single molecule and biochemical methods to better understand the kinetics and thermodynamics of protein-nucleic acid interactions. Current single molecule techniques used in the lab include Atomic Force Microscopy (AFM) and Total Internal Reflection Microscopy (TIRM) techniques such as Fluorescence Resonance Energy Transfer (FRET). A major focus of our lab is the characterization of both the static and the dynamic protein-nucleic acid interactions that govern the overall repair specificity of mismatched or damaged DNA in prokaryotic and eukaryotic organisms. A few questions we are addressing include the following: How is mismatch repair initiated on some mismatches but not others? What properties of a damaged DNA substrate initiate apoptosis over mismatch repair? What roles do the mismatch repair initiation proteins, MutS and MutL, play in that separation of pathways? What are the structures/conformations of the multi protein-DNA complexes that control DNA repair? We are also characterizing a host of other protein-DNA interactions involved in DNA repair. There are projects within the group that would appeal to most areas of interest. Our group is composed of students from a variety of backgrounds and departments including chemistry, materials science, physics, and biophysics.
The research in the Rubinstein Group is in the field of polymer theory and computer simulations. The unique properties of polymeric systems are due to the size, topology and interactions of the molecules they are made of. Our goal is to understand the properties of various polymeric systems and to design new systems with even more interesting and useful properties. Our approach is based upon building and solving simple molecular models of different polymeric systems. The models we develop are simple enough to be solved either analytically or numerically, but contain the main features leading to unique properties of real polymers. Computer simulations of our models serve as an important bridge between analytical calculations and experiments.
Developing novel materials and device architectures to further enhance the efficiency of polymer solar cells requires a fundamental understanding of the impact of chemical structures on photovoltaic properties. Given that device characteristics depend on many parameters, deriving structure/property relationships has been very challenging.
Through an international collaboration, members of the You Group discovered that a single parameter, hole mobility, determines the fill factor of bulk heterojunction photovoltaic devices in a series of copolymers with varying amount of fluorine substitution. The continuous increase of hole mobility upon further fluorination is related to a preferential face-on orientation and improved pi-pi stacking of the polymer backbones. The results shows the potential of properly-designed polymers to enable high fill factors in thick devices, as required by mass production technologies. These significant results appeared in JACS, and were also featured in JACS Spotlights.
Genetically encoded, light-activatable proteins provide the means to probe biochemical pathways at specific subcellular locations with exquisite temporal control. However, engineering these systems in order to provide a dramatic jump in localized activity, while retaining a low dark-state background remains a significant challenge.
When placed within the framework of a genetically encodable, light-activatable heterodimerizer system, the actin-remodelling protein cofilin induces dramatic changes in the F-actin network and consequent cell motility upon illumination. In an article published in Angewandte Chemie, International Edition, researchers in the David Lawrence Group, demonstrate that the use of a partially impaired mutant of cofilin is critical for maintaining low background activity in the dark. They also show that light-directed recruitment of the reduced activity cofilin mutants to the cytoskeleton is sufficient to induce F-actin remodeling, formation of filopodia, and directed cell motility.
As announced by Israeli Prime Minister Benjamin Netanyahu on October 6th, Arey Distinguished Professor of Chemistry, Thomas Meyer, is one of two winners of the 2014 Eric and Sheila Samson Prime Minister's Prize for Innovation in Alternative Fuels for Transportation. Professor Meyer is recognized as a world leader in solar fuel research.
The $1 million prize is awarded for breakthrough work into converting solar energy into electricity capable of powering transportation. "We are making a major multi-year effort so that we will not be dependent on fluctuations in the price of oil," Netanyahu said. "This prize gives the researchers true appreciation for their efforts." The Eric and Sheila Samson Prize, totaling $1 million, is the world’s largest monetary prize awarded in the field of alternative fuels, and is granted to scientists who have made critical advancements."
Congratulations to Dr. Meyer on receiving such a prestigious international honor," said UNC Chancellor Carol L. Folt. "Dr. Meyer is a superb example of the kind of innovation we champion here at UNC, using research to solve the world's most pressing problems. By pairing a basic scientific knowledge of photosynthesis with the latest advances in nanotechnology, Dr. Meyer and his team are bringing the world closer than ever to making solar energy a practical, reliable power source."
Caitlin McMahon, a fourth year graduate student in the Alexanian Group, has been selected by the ACS Division of Organic Chemistry to receive a 2014-2015 Graduate Fellowship. Awardees for this highly competitive award are selected by an independent committee, and evidence of research accomplishments is an important factor in the selection process. Caitlin will travel to the 2015 National Organic Symposium to present a poster of her research.
Caitlin's research focuses on the development of metal-catalyzed organic reactions, with the goal of discovering new ways to form carbon-carbon bonds and expanding the methodology available to synthesize organic building blocks. More specifically, she has developed a palladium-catalyzed, intermolecular Heck-type reaction using alkyl electrophiles - significantly expanding the scope of the widely-utilized Heck reaction. She is currently studying carbonylative metal-catalyzed reactions, building functionalized organic molecules by forming two carbon-carbon bonds in one step under mild conditions.
A p-type metal oxide with high surface area and good charge carrier mobility is of paramount importance for development of tandem solar fuel and dye-sensitized solar cell, DSSC, devices. Published in the Journal of Physical Chemistry, researchers in the Cahoon Group report the synthesis, hierarchical morphology, electrical properties, and DSSC performance of mesoscale p-type NiO platelets.
This material, which exhibits lateral dimensions of 100 nm but thicknesses less than 10 nm, can be controllably functionalized with a high-density array of vertical pores 4–6, 5–9, or 7–23 nm in diameter depending on exact synthetic conditions. Thin films of this porous but still quasi-two-dimensional material retain a high surface area and exhibit electrical mobilities more than 10-fold higher than comparable films of spherical particles with similar doping levels. These advantages lead to a modest, 20–30% improvement in the performance of DSSC devices under simulated 1-sun illumination. The capability to rationally control morphology provides a route for continued development of NiO as a high-efficiency material for tandem solar energy devices.
RNA molecules function as the central conduit of information transfer in biology. To do this, they encode information both in their sequences and in their higher-order structures. Understanding the higher-order structure of RNA remains challenging and slow. In work reported in PNAS and highlighted in Science, Phil Homan in the Weeks Lab led a collaboration that devised a simple, experimentally concise, and accurate approach for examining higher-order RNA structure.
The researchers used massively parallel sequencing to invent an easily implemented single-molecule experiment for detecting through-space interactions and multiple conformations in RNA. This strategy, called RING-MaP, can be used to analyze higher-order RNA structure, detect biologically important hidden states, and refine accurate three-dimensional structure models.
At the Department of Chemistry, we feel strongly that diversity is crucial to our pursuit of academic excellence, and we are deeply committed to creating a diverse and inclusive community. We support UNC's policy, which states that "the University of North Carolina at Chapel Hill is committed to equality of opportunity and pledges that it will not practice or permit discrimination in employment on the basis of race, color, gender, national origin, age, religion, creed, disability, veteran's status, sexual orientation, gender identity or gender expression."