We are interested in developing chemical biology tools for protein semi-synthesis, labeling and bioconjugation. We create synergy in protein engineering by fusing recombinant expression with chemical synthesis and enzymatic peptide ligation for potential applications in mechanistic biology and biotechnology. The unique engineering of hemoglobin to probe the dynamics in sickle hemoglobin fiber assembly, construction of well-defined multivalent antigens to elicit enhanced immune response, synthesis of neoglycoconjugates and SUMOylated peptides are illustrative examples in this regard.

Current work in our laboratory is focused toward understanding the mechanistic imperatives of sortase-catalyzed protein/peptide ligation and exploring innovative strategies to expand the synthetic ambit of this multifaceted enzyme. Our group has found new sortases endowed with orthogonal specificity for newer applications.

Our inter- and intra-institutional collaborations have enabled the development of a simple strategy for targeting antisense oligonucleotides and other therapeutics to macrophages, discovery of a new hemoglobin uptake mechanism in Leishmania donovani, elaboration of mycoketide biosynthesis catalyzed by polyketide synthases, and details of B cell responses to peptide epitopes and ascribing the role for a mycobacterial kinase.

• Fellow, Indian National Science Academy
• Fellow, The National Academy of Sciences, India
• Fellow, Indian Academy of Sciences
• J C Bose National Fellow (DST, Govt of india)
• National Bioscience Award (DBT, Govt of India)
• Biotechnology Overseas Associateship, (DBT, Govt of India)
• Ella Fitzgerald Fellowship (New York Heart Association, USA)
• Member, American Peptide Society
• Member, Guha Research Conference

• Patent No. 8148321; Novel bioconjugates as therapeutic agent and synthesis thereof, US Patent
• Patent No. 320958; Novel bioconjugates as therapeutic agents and synthesis thereof, Indian Patent
• Patent No. 358332; A Sortase-Click reaction suite for defined protein dendrimer assembly: Synthetic example of a multivalent vaccine, Indian Patent

1. Biswas T, Misra A, Das S, Yadav P, Ramakumar S, Roy RP (2020) Interrogation of 3D-swapped structure and functional attributes of quintessential Sortase A from Streptococcus pneumoniae. Biochem J 477: 4711-28.
2. Pawale VS, Yadav P and Roy RP (2018) Facile one-step assembly of bona fide SUMO conjugates by chemoenzymatic ligation. ChemBioChem 19: 1137-41.
3. Das S, Pawale VS, Dadireddy V, Singh AK, Ramakumar S and Roy RP (2017) Structure and specificity of a new class of Ca2+ independent housekeeping sortase from Streptomyces avermitilis provides insights into its non-canonical substrate preference. J Biol Chem 292:7244-57.
4. Biswas T, Pawale VS, Choudhury D and Roy RP (2014) Sorting of LPXTG peptide substrate by archetypal Sortase A. Biochemistry 53: 2515-24.
5. Gupta K, Singh S, Gupta K, Khan N, Sehgal D, Haridas V and Roy RP (2012) A bioorthogonal chemoenzymatic strategy for defined protein dendrimer assembly. ChemBioChem 13: 2489-94.
6. Dasgupta S, Samantaray S, Sahal D and Roy RP (2011) Isopeptide ligation catalyzed by quintessential Sortase A. J Biol Chem 286: 23996-24006.
7. Khan S, Nagarajan SN, Parikh A, Samantaray S, Singh A, Kumar D, Roy RP, Bhatt A and Nandicoori VK (2010) Phosphorylation of enoyl-acyl carrier protein reductase InhA impacts mycobacterial growth and survival. J Biol Chem 285: 37860-71.
8. Samantaray S, Marathe U, Dasgupta S, Nandicoori VK, Roy RP (2008) Peptide-sugar ligation catalyzed by transpeptidase Sortase. J Am Chem Soc 130: 2133-34.
9. Sudha R, Anantharaman L, Sivaram MV, Mirsamadi N, Choudhury D, Lohiya NK, Gupta RB, and Roy RP (2004) Linkage of interactions in sickle hemoglobin fiber assembly. J Biol Chem 279: 20018-27.
10. Balajee SR and Roy RP (2002) Volume exclusion effect as a driving force for reverse proteolysis. J Biol Chem 277: 43252-61.
11. Sivaram MV, Sudha R, Roy RP (2001) A role for α113 (GH1) amino acid residue in the polymerization of sickle hemoglobin. J Biol Chem 276: 18209-15.
12. Kumaran S, Datta D, Roy RP (2000) An enigmatic peptide ligation reaction. Protein Science 9: 734-41.
13. Prasad V, Hashim S, Mukhopadhyay A, Basu SK, Roy RP (1999) Oligonucleotides tethered to a short polyguanylic acid stretch are targeted to macrophages. Antimicrob Agents Chemother 43: 2689-96.
14. Sengupta S, Tripathi J, Tandon R, Raje M, Roy RP, Basu SK, Mukhopadhyay A (1999) Hemoglobin endocytosis in Leishmania is mediated through a 46-kDa protein located in the flagellar pocket. J Biol Chem 274: 2758-65.
15. Kumaran S, Datta D, Roy RP (1997) Conformationally driven protease-catalyzed splicing of peptide segments. Protein Science 6: 2233-41.