K. Das Gupta
Professor, Dept. Of Microbiology,
PhD: University of Calcutta (1989)
group has been investigating the Molecular Biology of Mycobacterial plasmids
and phages. These entities have been used extensively in the genetic
engineering of the TB pathogen Mycobacterium tuberculosis. Moreover
Phages and Plasmids are interesting systems for study as they are considered
to posses long evolutionary histories.
investigations have provided significant new information regarding how the
Mycobacterial plasmid pAL5000 replicates in its host. It was revealed, for
the first time that a novel mechanism exists by which a replication protein
(RepB) can be activated through coupled expression with another replication
protein (RepA). Investigations have also revealed how RepB initiates
replication by bending the pAL5000 origin of replication.
Another area of our research interest is ‘Genomics of Mycobacteriophages’.
My laboratory has characterized two key enzymes encoded by Mycobacteriophage
D29: a) Gp50, a Cyanocobalamin dependent Ribonucleotide Reductase and b)
Gp56, a Thymidylate Synthase (ThyX). Both these enzymes are considered to be
evolutionarily ancient indicating that Mycobacteriophages themselves may be
of ancient origin. Such a possibility is supported by the discovery of a
primitive RecA like protein (D29 Gp65) having just the ATPase core which
acted as an exonuclease.. Gp65 like proteins, representing the
ATPase core of RecA are often found in Archaebacteria and these could be
derived from a common ancestor that existed prior to the divergence of
Eubacteria and Archaebacteria.
Apart from these areas my lab is also interested in developing peptide based
diagnostic tools for TB using mimotopes of common Mycobacterial antigens.
Das Gupta, S. K., M. D.
Bashyam, and A. K. Tyagi.
1993. Cloning and assessment of mycobacterial promoters by using a plasmid
shuttle vector. J Bacteriol 175:5186-92.
DasGupta, S. K., S. Jain, D.
Kaushal, and A. K. Tyagi.
1998. Expression systems for study of mycobacterial gene regulation and
development of recombinant BCG vaccines. Biochem Biophys Res Commun 246:797-804.
Chawla, M., and S. K. Das
Transposition-induced structural instability of Escherichia coli-mycobacteria
shuttle vectors. Plasmid 41:135-40.
S., M. Mitra, and S. K. Das Gupta.
2000. A high yielding mutant of mycobacteriophage L1 and its application as
a diagnostic tool. FEMS Microbiol Lett 188:47-53.
A., M. Chawla-Sarkar, S. Chakrabarti, and S. K. Das Gupta.
2002. Origin binding activity of the Mycobacterial plasmid pAL5000
replication protein RepB is stimulated through interactions with host
factors and coupled expression of repA. J Bacteriol 184:2204-14.
A., S. Chatterjee, and S. K. Das Gupta.
2004. Translational coupling to an upstream gene promotes folding of the
mycobacterial plasmid pAL5000 replication protein RepB and thereby its
origin binding activity. J Bacteriol 186:335-42.
Saha, A., A. Sharma, A. Dhar,
B. Bhattacharyya, S. Roy, and S. K. Das Gupta.
2005. Antagonists of Hsp16.3, a low-molecular-weight mycobacterial chaperone
and virulence factor, derived from phage-displayed peptide libraries. Appl
Environ Microbiol 71:7334-44.
Sharma, A., A. Saha, S.
Bhattacharjee, S. Majumdar, and S. K. Das Gupta.
2006. Specific and randomly derived immunoactive peptide mimotopes of
mycobacterial antigens. Clin Vaccine Immunol 13:1143-54.
Chatterjee, S., A. Basu, A.
Basu, and S. K. Das Gupta.
2007. DNA bending in the mycobacterial plasmid pAL5000 origin-RepB complex.
J Bacteriol 189:8584-92.
Mandal, S., S. Chatterjee,
B. Dam, P. Roy, and S. K. Das Gupta.
2007. The dimeric repressor SoxR binds cooperatively to the promoter(s)
regulating expression of the sulfur oxidation (sox) operon of
Pseudaminobacter salicylatoxidans KCT001. Microbiology 153:80-91.
Bhattacharya, B., N. Giri,
M. Mitra, and S. K. Gupta.
2008. Cloning, characterization and expression analysis of nucleotide
metabolism-related genes of mycobacteriophage L5. FEMS Microbiol Lett
Das Gupta, T., B.
Bandyopadhyay, and S. K. Das Gupta.
2008. Modulation of DNA-binding activity of Mycobacterium tuberculosis HspR
by chaperones. Microbiology 154:484-90.
Giri, N., P. Bhowmik, B.
Bhattacharya, M. Mitra, and S. K. Das Gupta.
2009. The mycobacteriophage D29 gene 65 encodes an early-expressed protein
that functions as a structure-specific nuclease. J Bacteriol 191:959-67.