Dr. R. Suhas

Research Experience:

Summary of Postdoctoral Research Work:

Solid-phase peptide synthesis (SPPS) forms the basis of research. My research can be categorized into various sub-sections as briefly described below:

Peptide-based vaccine constructs (Dendrimerization): Bromomaleimide as a novel core has been added into the repertoire for the presentation of multiple branched peptides. Using this core two-, four- and eight-branched dendritic peptides have been synthesized under mild conditions. Further, highly chemoselective ligations have been performed for various peptide-ligands on this core. Also a strategy has been developed for stapling three different peptides on a single platform paving way for multidrug presentation/vaccine preparation.

Peptide diagnostics: a) DOTA, a tetra-aza metal chelator has been conjugated to a depsipeptide and radiolabelling studies using Ga have been done in animal model; b) NODAGA, a tri-aza cyclic chelator has been anchored to a 37 amino acids peptide (LL37) for radiochemistry-based studies using Ga; c) Colistin, a cyclic depsipeptide has been synthesized by a combination of solid- and solution-phase chemistries for radiolabelling studies.

On-resin synthesis of siderophores: First solid-phase total synthesis of different classes of siderophores, regarded as “synthetically difficult” peptidomimetics (including building blocks) has been carried out using robust chemistry.

Cyclic peptides: An improved and facile methodology has been developed for the construction of colistin-like peptide which is considered as the last line defense for fighting Gram-negative bacteria. This apart, we have demonstrated totally a new route for the construction cyclic peptides which comprises of a peptide-dendrimer, a spacer which can undergo reduction and form linking sites for cyclization.

Summary of Ph.D. Research Work:

“Design, Synthesis and Characterization of Novel Amino Acids or Peptides Conjugated Heterocycles of Biological Interest”

The research work chiefly consists of synthesis of heterocycles and peptides and their conjugation in solution phase. The work has been divided into various sections and is briefly given below:

Some shorter analogues of Bactenecin7 (Bac7) with different amino acid composition have been synthesized and conjugated to quinazolinone as antimicrobial agents. Elastin protein-based peptides viz., tetrapeptides, pentapeptides and tricosapeptides were synthesized by step-wise, (3+2) and [(5 + 5 + 5) + (5 + 5 + 5)] fragment coupling method respectively which were conjugated to piperidinyl and piperazinyl heterocycles. A relationship between hydrophobicity, chain length and antimicrobial activity has been established. A small library of urea/ thiourea derivatives of the elastin-based peptide conjugates. Few of the compounds have exhibited ~25 times high potency than the reference standard. A structure-activity relationship has been established.On the other hand, several analgesic and anti-inflammatory agents based on a natural product, aurantiamide acetate and indole (Trp) were synthesized.