216.368.3696 email@example.com Millis 214
Interests: Organic Chemistry, Protein Biochemistry, Chemical Biology, Chemical Synthesis and Characterization, Genetically-Encoded Natural Products, Molecular Biology, Microbial Genetics, Bioinformatics, Metabolic Pathways, Drug Discovery
Bachelor of Science (B. Sc): Madras University (The New College), Chennai, India, 1994 – 1997.
Master of Science (M. Sc): Indian Institute of Technology, Kanpur, India, 1997 – 1999.
Ph.D. Indiana University, Bloomington, 1999 – 2005.
Post-Doctoral Research, University of Utah, 2005 – 2008.
Teaching at Case Western Reserve University
|Fall 2008||Synthetic Methods in Organic Chemistry (CHEM 435)|
|Spring 2009||Advanced Organic Chemistry II (CHEM 422)|
|Fall 2009||Complex Molecular Synthesis (CHEM 436)|
|Spring 2010||Advanced Organic Chemistry II (CHEM 422)|
|Fall 2010||Synthetic Methods in Organic Chemistry (CHEM 435)|
|Fall 2011||Introductory Organic Chemistry Laboratory I (CHEM 233)|
|Spring 2012||Introductory Organic Chemistry Laboratory II (CHEM 234)|
|Fall 2012||Synthetic Methods in Organic Chemistry (CHEM 435)|
Research Projects in Viswanathan Group
Natural Product Biosynthetic Pathways from Cyanobacteria
|Figure 1. Left - Genomes in Tree of Life assembled by Joint Genome Institute. Cyanobacteria are a growing portion of the tree. Right - Our approach for studying biosynthetic pathways. Click the images for larger versions.|
Through 3.5 billion years of evolution, cyanobacteria continue to shape our planet’s biodiversity while serving as repositories of bioactive compounds. In Nature’s repositories of biodiversity (see Figure 1, top) cyanobacteria occupy a rapidly growing space as more genomic data become available. While marine cyanobacteria have been elegantly studied for natural product pathway research, terrestrial Group V cyanobacteria (filamentous and from soil) remain largely underexplored for their biosynthetic potential. We are carrying out one of the early efforts to collectively identify novel pathways for sustainable production of natural products from terrestrial Group V cyanobacteria. Figure 1 (bottom) shows the logical sequence of our investigations. Genome sequences collected by our group is routinely mined for unraveling the metabolic diversity of Terrestrial Group V Cyanobacteria through bioinformatics.
Three aims that help us realize the overall goal are to:
- Clone and heterologously express novel classes of enzymes.
- Functionally and mechanistically characterize key steps of the biosynthetic pathway.
- Apply chemoenzymatic steps to combinatorially biosynthesize novel biosynthetic products.
Biosensors for Catalysis and Detection
New genomes require novel ways to reliably identify protein function. Therefore new biochip forming strategies are urgently needed. One of the seminal discoveries our laboratory pursues is toward designing small molecule-engineered protein biochips. We have developed a new class of electrophiles named smSNAREs that help capture GST or its fusion proteins with remarkable selectivity and ease. Figure 2 shows the details of this strategy.
Suitably modified/tagged proteins are anchored to solid surfaces to result in uniform and reliable orientation. Newly identified biosynthesis enzymes from genomes of microbial organisms become ideal targets to employ this technology to help create enzymatic assays with resource-economy. Recent results from our laboratory reveal that ubiquitous enzymes such as Glutatione S-Transferases can be quite useful to catalyze the immobilization of small-molecules to glass surfaces.
Recently, our work on GST-catalyzed Single Step Protein Immobilization is featured in Bioconjugate Chemistry and The Journal of Organic Chemistry.
Selected Recent Publications
- Viswanathan, R.; Labadie, G. R.; Poulter, C. D.* "Regioselective Covalent Immobilization of Catalytically Active Glutathione S-Transferase on Glass Slides" Bioconjugate Chem., 2013, 24, 571-577. [Link]
- Voelker, A. E. and Viswanathan, R.* "Self-Catalyzed Immobilization of GST-Fusion Proteins for Genome-Encoded Biochips" Bioconjugate Chem., 2013, 24, 1295-1301. [Link]
- Voelker, A. E. and Viswanathan, R.* "Synthesis of a Suite of Bioorthogonal GST Substrates and Their Enzymatic Incorporation for Protein Immobilization" J. Org. Chem. 2013, 78, 9647-9658. [Link]
- Yu, G.; Kuo, D.; Shoham, M. and Viswanathan, R.* "Synthesis and in vitro Evaluation of a Biaryl Hydroxyketone Library as Antivirulence Agents against MRSA" ACS Comb. Sci. 2014, 16, 85–91. [Link]
- Liu, Z.; Reba, S.; Chen, W-D.; Boom, W. H.; Porwal, S. K.; Viswanathan, R. and Devireddy, L.* "Regulation of mammalian siderophore 2,5-DHBA in the innate immune response to infection" J. Exp. Med. 2014, 211, 1197-1213. [Link]
- Porwal, S. K.; Furia, E.; Harris, M. E.; Viswanathan, R.* and Devireddy, L.* "Synthetic, Potentiometric and Spectroscopic Studies of Chelation between Fe(III) and 2, 5-DHBA Supports Salicylate-Mode of Siderophore Binding Interactions" J. Inorg. Biochem. in Press.
- Melinda L. Micallef, Deepti Sharma, Brittney M. Bunn, Lena Gerwick, Rajesh Viswanathan*, Michelle C. Moffitt* "Comparative analysis of hapalindole, ambiguine and welwitindolinone gene clusters and reconstitution of indole-isonitrile biosynthesis from cyanobacteria" BMC Microbiology, in Press.
* corresponding author