The Redinbo Laboratory uses the tools of structural, molecular and chemical biology to examine a range of dynamic cellular processes central to human health. Current projects include the discovery of new antimicrobials targeted to drug-resistant bacteria, the design of novel proteins engineered to detect and eliminate toxic chemicals, and the development of small-molecule to cell-based methods to improve anticancer chemotherapeutics. In addition, we continue to focus on determining the crystal structures of macromolecular complexes, including those involving human nuclear receptors central to transcriptional regulation, bacterial proteins involved in DNA manipulation and human cell contact, and enzymes central to key cellular processes.
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.
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.
Dark-field microscopy, DFM, is widely used to optically image and spectroscopically analyze nanoscale objects. In a typical DFM configuration, a sample is illuminated at oblique angles and an objective lens collects light scattered by the sample at a range of lower angles. As demonstrated in an article published as the cover of ACS Photonics, researchers in the Cahoon Group have developed waveguide scattering microscopy, WSM, as an alternative technique to image and analyze photonic nanostructures. WSM uses an incoherent white-light source coupled to a dielectric slab waveguide to generate an evanescent field that illuminates objects located within several hundred nanometers of the waveguide surface.
Using standard microscope slides or coverslips as the waveguide, the group demonstrate high-contrast dark-field imaging of nanophotonic and plasmonic structures such as Si nanowires, Au nanorods, and Ag nanoholes. Scattering spectra collected in the WSM configuration show excellent signal-to-noise with minimal background signal compared to conventional DFM. In addition, the polarization of the incident field is controlled by the direction of the propagating wave, providing a straightforward route to excite specific optical modes in anisotropic nanostructures by selecting the appropriate input wavevector. Considering the facile integration of WSM with standard microscopy equipment, the Cahoon Group scientists anticipate it will become a versatile tool for characterizing photonic nanostructures.
Francis Preston Venable Professor of Chemistry, Joseph Templeton, is the recipient of this year's Thomas Jefferson award, which was presented to him by Chancellor Folt at a recent Faculty Council meeting. "I would just like to add from my own chance to work so closely with Professor Templeton the last year how deserving and wonderful this award is," said Chancellor Folt.
The Thomas Jefferson Award was established in 1961 by the Robert Earll McConnell Foundation. It is presented annually to "that member of the academic community who through personal influence and performance of duty in teaching, writing, and scholarship has best exemplified the ideals and objectives of Thomas Jefferson." This award is, according to Department Chair, Professor Valerie Ashby, "a well-deserved honor for Professor Templeton that recognizes the many forms of his contributions to the university throughout his career."
Many central biological processes are mediated by complex RNA structures, but the higher-order interactions for most RNAs are unknown, which makes it difficult to understand how RNA structure governs function. As published in Nature Methods, a team of students in the Weeks lab have invented a new approach -- selective 2'-hydroxyl acylation analyzed by primer extension and mutational profiling (SHAPE-MaP) -- that makes possible de novo and large-scale identification of RNA functional motifs.
SHAPE-MaP melds chemistry invented in the Weeks lab with readout by massively parallel sequencing to make it possible to detect structure-selective chemical reactions in RNA on genome-wide scales. SHAPE-MaP represents a "no compromises" approach for interrogating the structure of RNA, enables analysis of low-abundance RNAs, and is ultimately poised to democratize RNA-structure analysis.
Carolina Chemistry Professor Maurice Brookhart has been selected to receive the 2015 Gabor A. Somorjai ACS National Award for Creative Research in Catalysis. The award recognizes outstanding theoretical, experimental, or developmental research resulting in the advancement of understanding or application of catalysis, and consists of a $5,000 cash prize along with a certificate and up to $2,500 for travel expenses to the meeting at which the award will be presented.
Professor Brookhart was recently highlighted by the National Science Foundation for his ground-breaking contributions to the improvement of the process used to create alternative fuels. He is part of a team of scientists who have invented and patented, and are bringing toward commercialization, catalysts that will convert light hydrocarbons into diesel fuel. The improved process can create diesel in a less expensive, cleaner way, whether it is diesel made from traditional sources, such as oil, or alternative sources, such as biomass.
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."