https://dspace.nii.res.in//https://dspace.nii.res.in/handle/123456789/123 2026-04-04T21:49:25Z 2026-04-04T21:49:25Z Arora, Ashish Dasgupta, Arunava Biswal, Bichitra Kumar Jain, Anupam Tripathi, Sarita Pal, Ravi Kant Singh, Shriya Zohib, Muhammad Yadav, Vikash https://dspace.nii.res.in//https://dspace.nii.res.in/handle/123456789/1629 2025-07-10T12:14:13Z 2025-01-01T00:00:00Z

Title: Structural and biophysical characterization of PadR family protein Rv1176c of Mycobacterium tuberculosis H37Rv Authors: Arora, Ashish; Dasgupta, Arunava; Biswal, Bichitra Kumar; Jain, Anupam; Tripathi, Sarita; Pal, Ravi Kant; Singh, Shriya; Zohib, Muhammad; Yadav, Vikash Abstract: Rv1176c of Mycobacterium tuberculosis H37Rv belongs to the PadR-s1 subfamily of the PadR family of protein. Rv1176c forms a stable dimer in solution. Its stability is characterized by a thermal melting transition temperature (Tm) of 39.4 °C. The crystal structure of Rv1176c was determined at a resolution of 2.94 Å, with two monomers in the asymmetric unit. Each monomer has a characteristic N-terminal winged-helix-turn-helix DNA-binding domain. Rv1176c C-terminal is a coiled-coil dimerization domain formed of α-helices α5 to α7. In the Rv1176c dimer, there is domain-swapping of the C-terminal domain in comparison to other PadR homologs. In the dimer, there is a long inter-subunit tunnel in which different ligands can bind. Rv1176c was found to bind to the promoter region of its own gene with high specificity. M. smegmatis MC2 155 genome lacks homolog of Rv1176c. Therefore, it was used as a surrogate to characterize the functional role of Rv1176c. Expression of Rv1176c in M. smegmatis MC2 155 cells imparted enhanced tolerance towards oxidative stress. Rv1176c expressing M. smegmatis MC2 155 cells exhibited enhanced intracellular survival in J774A.1 murine macrophage cells. Overall, our studies demonstrate Rv1176c to be a PadR-s1 subfamily transcription factor that can moderate the effect of oxidative stress.

2025-01-01T00:00:00Z Biswal, Bichitra K Bhatia, Indu Yadav, Savita https://dspace.nii.res.in//https://dspace.nii.res.in/handle/123456789/1487 2025-12-05T12:47:57Z 2022-01-01T00:00:00Z

Title: Identification, structure determination and analysis of Mycobacterium smegmatis acyl-carrier protein synthase (AcpS) crystallized serendipitously Authors: Biswal, Bichitra K; Bhatia, Indu; Yadav, Savita Abstract: The unintended crystallization of proteins which generally originate from the expression host instead of the target recombinant proteins is periodically reported. Despite the massive technological advances in the field, assigning a structural model to the corresponding diffraction data is not a trivial task. Here, the structure of acyl-carrier protein synthase (AcpS) from Mycobacterium smegmatis (msAcpS), which crystallized inadvertently in an experimental setup to grow crystals of a Mycobacterium tuberculosis protein using M. smegmatis as an expression system, is reported. After numerous unsuccessful attempts to solve the structure of the target protein by the molecular-replacement method no convincing solutions were obtained, indicating that the diffraction data may correspond to a crystal of an artifactual protein, which was finally identified by the Sequence-Independent Molecular replacement Based on Available Databases (SIMBAD) server. The msAcpS structure was solved at 2.27 Å resolution and structural analysis showed an overall conserved fold. msAcpS formed a trimeric structure similar to those of other reported structures of AcpS from various organisms; however, the residues involved in trimer formation are not strictly conserved. An unrelated metal ion (Ni2+), which was possibly incorporated during protein purification, was observed in the proximity of His49 and His116. Structural and sequence differences were observed in the loop connecting the α3 and α4 helices that is responsible for the open and closed conformations of the enzyme. Moreover, the structural analysis of msAcpS augments the current understanding of this enzyme, which plays a crucial role in the functional activation of acyl-carrier proteins in the fatty-acid biosynthesis pathway.

2022-01-01T00:00:00Z Biswal, Bichitra K Yadav, Savita Bhatia, Indu https://dspace.nii.res.in//https://dspace.nii.res.in/handle/123456789/1486 2025-12-05T12:47:40Z 2022-01-01T00:00:00Z

Title: Identification, structure determination and analysis of Mycobacterium smegmatis acyl-carrier protein synthase (AcpS) crystallized serendipitously Authors: Biswal, Bichitra K; Yadav, Savita; Bhatia, Indu Abstract: The unintended crystallization of proteins which generally originate from the expression host instead of the target recombinant proteins is periodically reported. Despite the massive technological advances in the field, assigning a structural model to the corresponding diffraction data is not a trivial task. Here, the structure of acyl-carrier protein synthase (AcpS) from Mycobacterium smegmatis (msAcpS), which crystallized inadvertently in an experimental setup to grow crystals of a Mycobacterium tuberculosis protein using M. smegmatis as an expression system, is reported. After numerous unsuccessful attempts to solve the structure of the target protein by the molecular-replacement method no convincing solutions were obtained, indicating that the diffraction data may correspond to a crystal of an artifactual protein, which was finally identified by the Sequence-Independent Molecular replacement Based on Available Databases (SIMBAD) server. The msAcpS structure was solved at 2.27 Å resolution and structural analysis showed an overall conserved fold. msAcpS formed a trimeric structure similar to those of other reported structures of AcpS from various organisms; however, the residues involved in trimer formation are not strictly conserved. An unrelated metal ion (Ni2+), which was possibly incorporated during protein purification, was observed in the proximity of His49 and His116. Structural and sequence differences were observed in the loop connecting the α3 and α4 helices that is responsible for the open and closed conformations of the enzyme. Moreover, the structural analysis of msAcpS augments the current understanding of this enzyme, which plays a crucial role in the functional activation of acyl-carrier proteins in the fatty-acid biosynthesis pathway.

2022-01-01T00:00:00Z Biswal, Bichitra Kumar Srichandan, Sudeepa Meena, Jairam Panda, Amulya K Ahuja, Rahul https://dspace.nii.res.in//https://dspace.nii.res.in/handle/123456789/1485 2025-12-05T12:45:49Z 2023-01-01T00:00:00Z

Title: Immunogenicity Evaluation of Thermostable Microparticles Entrapping Receptor Binding Domain of SARS-CoV-2 by Single Point Administration Authors: Biswal, Bichitra Kumar; Srichandan, Sudeepa; Meena, Jairam; Panda, Amulya K; Ahuja, Rahul Abstract: Receptor binding domain (RBD) of SARS-CoV-2 is a prime vaccine target against which neutralizing antibody responses are directed. Purified RBD as a vaccine candidate warrants administration of multiple doses along with adjuvants and use of delivery systems to improve its immunogenicity. The present investigation examines the immunogenicity of RBD delivered by biodegradable polymer particles from single dose administration. Mice upon single point immunization of RBD entrapped microparticles generated improved antibody response. The polymer microparticles showed better temperature stability and could be stored at 37 degrees for one month without any considerable loss of immunogenicity. Further, immunization with microparticles could elicit memory antibody response upon challenge after four months of single dose administration. Thus, using microparticles entrapping RBD as a vaccine candidate confer improved immunogenicity, temperature stability and recall response. These thermostable microparticles seem to be a potentially cost-effective approach which can help in dose reduction, provide a wider access of vaccines and accelerate the end of global pandemic.

2023-01-01T00:00:00Z