The Jeff Johnson Group focuses on the development of new synthetic methods for the assembly of stereochemically complex small molecules. We are particularly interested in the design and synthesis of tailor-made reagents and catalysts for multicomponent reactions. In our recent investigations of several interesting problems, our continuing interest in the exploitation of ring strain as a source of novel reactivity led us to some mechanistically unusual heterocycle-forming cycloadditions of cyclopropanes and aldehydes. On another front, we are interested in the development of dipolar synthons for the coupling of complementary nucleophilic and electrophilic reaction partners. Our development of silyl glyoxylate reagents is an example of work in this area.
Members of the Ashby Group focus on the synthesis of functionalized materials with applications ranging from biology to alternative energy. We synthesize degradable polyester based material to take advantage of their enhanced biocompatibility and high degree of physical and chemical control. The materials we have synthesized range in applications from cell scaffolds to degradable shape memory devices.
A need in current biomaterials is the integration of functional groups into degradable polymers to impart properties for specialized applications. Two methods we employ utilize cyclization chemistry through "click" type reactions and Diels-Alder chemistry to integrate polar groups into a polyester backbone. Group members are also investigating functionalization chemistry based on aminooxy coupling reactions.
The National Science Foundation, NSF, is celebrating the achievements of five leading Science and Technology Centers, STC, that have been conducting world-class research and education programs since 2000 in varied disciplines with NSF funding. Each STC received a total of $38 million under its own cooperative agreement with NSF that concluded in 2010. Among the five centers recognized is the Science and Technology Center for Environmentally Responsible Solvents and Processes under the direction of UNC Chemistry faculty member Joseph DeSimone.
This STC is the world's leading center for enabling and discovering sustainable processes and products that use CO2-related technology. In addition, by fostering innovation and applying its discoveries to the development of sustainable energy alternatives, medical diagnostics and therapeutics via targeted delivery, its achievements have had broad societal benefits, including the catalytic role of its launch of eight start-up companies. Additionally, they have successfully engaged the public in science through various forums, including the NBTC Nanobiotechnology Center's traveling exhibit, It's a Nanoworld.
The central role of RNA polymerase (RNAP) is to catalyze the processive synthesis of a growing RNA transcript. Recent structural and biophysical data have led to a deeper understanding of the nucleotide addition cycle and insight into the structure–function relationships that govern transcription elongation.
In a collaborative review, Dorothy Erie discusses kinetic data on nucleotide incorporation in the context of crystal structures, which show RNAP in multiple conformations. The review presents a facilitated Brownian ratchet model of nucleotide incorporation, in which templated NTP binding to a non-catalytic site in the main channel promotes the conformational changes that lead to opening of the catalytic site and translocation.
In the first of two back-to-back communications in the same issue of Angewandte Chemie, the Lin Group describes the design of Nanoscale Coordination Polymers, NCPs, as potential contrast agents for computed tomography, CT, a biomedical imaging technique based on X-ray attenuation of a specimen.
The NCPs were synthesized using an iodinated ligand to carry high payloads of iodine, ca. 63 wt%, which allows for high X-ray attenuation as demonstrated by phantom studies. This type of nanomaterial offers a new strategy for designing efficient CT contrast agents that do not suffer from the inherent drawbacks of small-molecule agents. The work was carried out in collaboration with Professor Otto Zhou and his group in the Physics Department at UNC-Chapel Hill.
Parastoo Hashemi, a Postdoctoral Scholar in the Wightman Group, has been selected as the student recipient of the 2010 University Awards for the Advancement of Women. This prestigious award, given by the Chancellor's Office, is in its fifth year and was created to recognize individuals for their contributions on behalf of women at the University of North Carolina at Chapel Hill.
Although overexpression and 15N enrichment facilitate the observation of resonances from disordered proteins in Escherichia coli, 15N enrichment alone is insufficient for detecting most globular proteins. Published in JACS and subsequently mentioned in C&EN, the Pielak Group explains this dichotomy and overcomes the problem while extending the capability of in-cell NMR by using 19F-labeled proteins.
Resonances from small (∼10 kDa) globular proteins containing the amino acid analogue 3-fluoro-tyrosine can be observed in cells, but for larger proteins the 19F resonances are broadened beyond detection. Incorporating the amino acid analogue trifluoromethyl-L-phenylalanine allows larger proteins (up to 100 kDa) to be observed in cells. The Pielak Group researchers also show that site-specific structural and dynamic information about both globular and disordered proteins can be obtained inside cells by using 19F NMR.
Carolina Chemistry Research Assistant Professor Brian Hogan has been selected as recipient of a Chapman Family Faculty Fellowship. This recognition provides semester-long, on-campus fellowships for faculty who have distinguished teaching records at UNC and regularly teach undergraduate students.
The Chapman Family Faculty Fellowship has been created especially to recognize outstanding teachers in the College of Arts and Sciences, to foster more discussion of teaching, and to enrich teaching at a research University. Professor Hogan was selected based on the quality of his application proposal and his record as an outstanding and dedicated teacher. Our department congratulates Brian Hogan on this well-earned recognition.