个人简介
Ph.D., Vanderbilt University, 2010
研究领域
Carbohydrate Synthesis
Peptide Synthesis
Small Molecule Total Synthesis
Our research focuses on developing new tools to broaden our fundamental understanding of chemistry while addressing problems significant to human health. To achieve this objective, we divide our efforts between two broadly defined areas, bio- and glycoconjugate assembly and natural product total synthesis. Since our goal is to interface our synthetic efforts with issues of therapeutic application, we value interdisciplinary collaborations with biologists who aid in evaluation of the molecules we prepare. This approach, which is fostered by the Vanderbilt Institute of Chemical Biology, is a critical aspect of our program.
I. Synthesis & Evaluation of Human Milk Oligosaccharide & Related Glycoconjugates.
The 3rd largest component of breast milk, human milk oligosaccharides (HMOs) represent a large group of heterogeneous glycans, which can incorporate well above thirty residues per molecule. Because HMOs are largely indigestible, glycans with shorter chains are believed to serve as prebiotics that stimulate the growth of beneficial bacteria in the infant gut. HMOs with longer chains are believed to mimic carbohydrates on the intestinal surface where they serve as decoys for pathogenic bacteria. Due to the sheer volume of structures produced, it is unclear what structures (and in what quantity) are required to obtain the beneficial effects of breast milk.
Since the development of new approaches to assemble glycoconjugates is a major point of interest in our lab, this program will study the glycobiology of human milk by synthesizing homogeneous human milk oligosaccharides (HMOs), and related constructs, to investigate their use as pro- and antibiotics in infant formula. Globally, we view this program as an opportunity to use synthetic organic chemistry to control the composition of the infant gut flora and influence other biological processes.
II. Site-Specific Protein Modifications.
The biological roles of proteins are often determined by their co- and post-translational modifications. The resulting constructs play a fundamental role in an array of biological processes varying from mediating protein folding to cell recognition. Because most strategies for chemical protein modification rely on manipulation of nucleophilic amino acid side chains such as lysine or cysteine, our lab seeks to expand the reaction space this process occupies by developing new strategies for site-specific protein modification.
III. Natural Product Total Synthesis.
Our total synthesis projects are designed to challenge the state-of-the-art in organic synthesis. We choose target molecules that are structurally unique such as cyclic peptides that incorporate unnatural amino acids and terpenes featuring C- and/or O-glycosylation. Moreover, each target we select has interesting, unstudied biological properties (e.g. anticancer, antibacterial, and immunosuppression). Ultimately, it is our goal to synthesize compounds that can be used as tools to answer greater biological questions or provide a starting point for the development of therapeutics
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Steven D. Townsend, Audrey G. Ross, Kai Liu, and Samuel J. Danishefsky. Stereospecific Cis and Trans Ring Fusions Arising From Common Intermediates. Proceedings of the National Academy of Sciences of the United States of America. 2014, 0 (0): [Epub ahead of print].
Steven D. Townsend and Gary A. Sulikowski. Progress toward the Total Synthesis of Bielschowskysin. Organic Letters. 2013, 15 (19): 5096-5098.
Audrey G. Ross, Steven D. Townsend, and Samuel J. Danishefsky. Halocycloalkenones as Diels-Alder Dienophiles. Applications to Generating Useful Structural Patterns. The Journal of Organic Chemistry. 2013, 78 (1): 204-210.
Jianfeng Li, Suwei Dong, Steven D. Townsend, Thomas Dean, Thomas J. Gardella, and Samuel J. Danishefsky. Chemistry as an Expanding Resource in Protein Science. Fully Synthetic and Fully Active Human Parathyroid Hormone-Related Protein (1-141). Angewandte Chemie International Edition. 2012, 51 (49): 12263-12267.
Ping Wang, Suwei Dong, John A. Brailsford, Karthik Iyer, Steven D. Townsend, Qiang Zhang, Ronald Henderickson, JaeHung Shieh, Malcolm A. S. Moore, and Samuel J. Danishefsky. At Last: Erythropoietin as a Single Glycoform. Angewandte Chemie International Edition. 2012, 51 (46): 11576-11584.
Steven D. Townsend, Xiangyang Wu, and Samuel J. Danishefsky. Enhancing the Scope of the Diels-Alder Reaction through Isonitrile Chemistry: Emergence of a New Class of Acyl Activated Dienophiles. Journal of the American Chemical Society. 2012, 134 (25): 10659-10663.
Steven D. Townsend, Zhongping Tan, Suwei Dong, Shiying Shang, John A. Brailsford, and Samuel J. Danishefsky. Advances in Proline Ligation. Journal of the American Chemical Society. 2012, 134 (8): 3912-3916.
Haibo Yu, Meng Wu, Steven D. Townsend, Beiyan Zou, Shunyou Long, J. Scott Daniels, Owen B. McManus, Min Li, Craig W. Lindsley, and Corey R. Hopkins. Discovery, Synthesis, and Structure–Activity Relationship of a Series of N-Aryl-bicyclo[2.2.1]heptane-2-carboxamides: Characterization of ML213 as a Novel KCNQ2 and KCNQ4 Potassium Channel Opener. American Chemical Society. 2011, 2 (10): 572–577.
Alexis S. Hammond, Alice L. Rodriguez, Steven D. Townsend, Colleen M. Niswender, Karen J. Gregory, Craig W. Lindsley, and P. Jeffrey Conn. Discovery of a Novel Chemical Class of mGlu5 Allosteric Ligands with Distinct Modes of Pharmacology. ACS Chemical Neuroscience. 2011, 1 (10): 702–716.