Research Groups
Mammalian Biology: Recombinant Gene Products
Research Interests and Description
Staff Research Scientist: Anand Ranganathan, PhD
Group Leader: Navin Khanna
Research Interests
Genetically engineered biomolecules, codon-shuffling, pathogenesis of tuberculosis and dengue.
Description of Research
Our lab has developed a method for laboratory-directed evolution of proteins, called codon-shuffling. The potential of this method to create stand-alone de novo protein/peptide libraries, for eventual use as antibacterial entities was recently realized with the selection of some codon-shuffled, de novo proteins that were antibacterial in nature. The extent of their activity was studied by growth-inhibition and zone-clearance experiments, as well as by Electron Microscopy. All such proteins exhibited good secondary structure attributes, as judged by circular-dichroism spectroscopy and theoretical predictions.
Current efforts are now directed towards extending the method to create similar antibacterial proteins against pathogenic organisms like Mycobacterium tuberculosis. We have recently unearthed potent binders against an essential protein of M. tuberculosis, called hupB. Expression of this codon-shuffled protein in Mycobacteria caused growth retardation, as well as other effects commensurate with the inhibition of hupB inside mycobateria.
We have recently developed a three-hybrid system to probe in vivo protein-protein interactions, and have applied it to study the essential proteins of the RD1 complex of M. tuberculosis, namely ESAT6, CFP10, and Rv3871. We have demonstrated this by using CFP10 protein as a disruptor of a previously established interaction between ESAT6 and a small peptide, HCL1; at the same time, we have shown that CFP10 is not able to disrupt the strong interaction between ESAT6 and peptide SL3. The latter is being studied for its effects on the growth and virulence of M. tuberculosis.
In an effort to identify crucial protein-protein interactions that allow the pathogen to survive and propagate, we have recently shown that the M. tuberculosis response regulator, Rv1626, interacts with mammalian cytoskeleton protein complex Arp2/3. This finding, we believe, has implications for in vivo mycobacterial survival and pathogenesis and we are currently using the three-hybrid system to discover potent protein/peptide binders that are able to effectively disrupt the interaction.
Our laboratory has recently initiated a program to discover binders of the Domain III of the Dengue Virus envelope protein; domain III has been implicated in the dengue virus entry into mammalian cells. Our aim is to use the discovered binders to effectively prevent the viral entry.
Recent Publications
Kumar, K., Tharad, M., Ganapathy, S., Ram, G., Narayan, A., Khan, J.A., Pratap, R., Ghosh, A., Samuchiwal, S.K., Kumar, S., Bhalla, K., Gupta, D., Natarajan, K., Singh, Y., Ranganathan, A. 2009. Phenylalanine-rich peptides potently bind ESAT6, a virulence determinant of Mycobacterium tuberculosis, and concurrently affect the pathogen's growth. PLoS One 10, e7615 PubMed link
Rao, A., Ram, G., Saini, A.K., Vohra, R., Kumar, K., Singh, Y., Ranganathan, A. 2007. Synthesis and selection of de novo proteins that bind and impede cellular functions of an essential mycobacterial protein. Appl Environ Microbiol 73, 1320-1331 PubMed link
Gopalan, G., Chopra, S., Ranganathan, A., Swaminathan, K. 2006. Crystal structure of uncleaved L-aspartate-alpha-decarboxylase from Mycobacterium tuberculosis. Proteins 65, 796-802 PubMed link
Rao, A., Chopra, S., Ram, G., Gupta, A., Ranganathan, A. 2005. Application of the "codon-shuffling" method. Synthesis and selection of de novo proteins as antibacterials. J Biol Chem 280, 23605-23614 PubMed link
