Debasish Chattopadhyay

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The Ca(2+)-dependent cysteine protease calpain along with its endogenous inhibitor calpastatin is widely distributed. The interactions between calpain and calpastatin have been studied to better understand the nature of calpain inhibition by calpastatin, which can aid the design of small molecule inhibitors to calpain. Here we present the crystal structure(More)
Bacterially expressed unphosphorylated P protein of Chandipura Virus was found to be efficiently phosphorylated in vitro by casein kinase II (CKII). The phosphorylated form of the P protein supported the transcription in vitro but the unphosphorylated form could not. Kinetic data suggests that CKII incorporates one molecule of phosphate. Western blotting(More)
Amino acid sequences of nucleocapsid proteins are mostly conserved among different rhabdoviruses. The protein plays a common functional role in different RNA viruses by enwrapping the viral genomic RNA in an RNase-resistant form. Upon expression of the nucleocapsid protein alone in COS cells and in bacteria, it forms large insoluble aggregates. In this(More)
The flagellate protozoan parasite Trypanosoma cruzi is the pathogenic agent of Chagas disease (also called American trypanosomiasis), which causes approximately 50,000 deaths annually. The disease is endemic in South and Central America. The parasite is usually transmitted by a blood-feeding insect vector, but can also be transmitted via blood transfusion.(More)
The three dimensional structure of calcium-bound domain VI of porcine calpain has been determined to 1.9 A resolution. The crystal structure reveals five EF-hands, one more than previously suggested. There are two EF-hand pairs, one pair (EF1-EF2) displays an 'open' conformation and the other (EF3-EF4) a 'closed' conformation. Unusually, a calcium atom is(More)
Dihydrofolate reductase (DHFR) of the parasite Trypanosoma cruzi (T. cruzi) is a potential target for developing drugs to treat Chagas' disease. We have undertaken a detailed structure-activity study of this enzyme. We report here synthesis and characterization of six potent inhibitors of the parasitic enzyme. Inhibitory activity of each compound was(More)
Encapsidation of nascent genome RNA into an RNase-resistant form by nucleocapsid protein, N is a necessary step in the rhabdoviral life cycle. However, the precise mechanism for viral RNA specific yet processive encapsidation remains elusive. Using Chandipura virus as a model system, we examined RNA binding specificity of N protein and dissected the(More)
Uracil-DNA glycosylases (UDGs) are evolutionarily conserved DNA repair enzymes that initiate the base excision repair pathway and remove uracil from DNA. The UDG superfamily is classified into six families based on their substrate specificity. This review focuses on the family I enzymes since these are the most extensively studied members of the(More)
The molecular events associated with the transcriptive and replicative cycle of negative-stranded RNA viruses are still an enigma. We took Chandipura virus, a member of the Rhabdoviridae family, as our model system to demonstrate that Phosphoprotein P, besides Nucleocapsid protein N, also acts as a leader RNA-binding protein in its unphosphorylated form,(More)
The structure, function and reaction mechanism of glyceraldehyde 3-phosphate dehydrogenase (GAPDH) have been extensively studied. Based on these studies, three anion binding sites have been identified, one 'Ps' site (for binding the C-3 phosphate of the substrate) and two sites, 'Pi' and 'new Pi', for inorganic phosphate. According to the original flip-flop(More)