Agarwal, Mahesh2019-07-152023-10-192019-07-152023-10-192017ROLL NO.126106022https://gyan.iitg.ac.in/handle/123456789/1213Supervisor: Biplab BoseDiphtheria toxin (DT) is a well characterized AB-toxin with three independent domains: C-domain for catalysis and toxicity, T-domain for translocation through the membrane and R-domain or receptor-binding domain. The toxicity of DT has been investigated extensively and is utilized to create therapeutic agents, like immunotoxins, which kill cells. However, the receptor-binding ability of DT is not extensively explored and used for therapeutic purposes. The receptor of DT is Heparin-binding EGF-like growth factor (HB-EGF). It is expressed as a membrane-bound molecule, which is eventually released by ectodomain shedding. HB-EGF is a growth factor. It is overexpressed in various cancer cells and activates different oncogenic signaling pathways. Therefore, HB-EGF on the cell surface can be targeted for cell-specific drug delivery. It can also be targeted to modulate its oncogenic signaling. In the current work, we have manipulated the receptor-binding domain of Diphtheria toxin (RDT) in two ways. First, we have used recombinant RDT to deliver drug-loaded nanoparticles to specific cells that express Human HB-EGF. In the second part, we have established that a short stretch of 26 amino acids in RDT is adequate for binding to HB-EGF with moderate affinity.enBIOSCIENCES AND BIOENGINEERINGThesis