Supriya Das
Indian Institute of Chemical Biology
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Publication
Featured researches published by Supriya Das.
Journal of Organic Chemistry | 2015
Kanchan Mal; Supriya Das; Nakul C. Maiti; Ramalingam Natarajan; Indrajit Das
The potential of β,γ-unsaturated α-ketothioesters participating in hetero-Diels-Alder reaction has remained unexplored. We report herein the first study of a ZnI2-catalyzed highly diastereoselective inverse electron demand hetero-Diels-Alder reaction of β,γ-unsaturated α-ketothioesters with olefins to access highly substituted 3,4-dihydro-2H-pyrans. All the reactions proceed with cis-selectivity in moderate to excellent yields. Under similar reaction conditions, terminal alkynes undergo direct conjugate 1,4-addition to yield δ,ε-acetylenic α-ketothioesters. Furthermore, the utility of these cycloadducts has been demonstrated by an NBS-MeOH mediated stereospecific efficient access to fully substituted pyran rings. The product bromoethers undergo E2 elimination with DBU, resulting in substituted 3,6-dihydro-2H-pyrans. In addition, the thioester moiety of the products has been used for further transformations, such as amidations and Fukuyama coupling reactions.
PLOS ONE | 2014
Swagata Das; Uttam Pal; Supriya Das; Khyati Bagga; Anupam Roy; Arpita Mrigwani; Nakul C. Maiti
An amyloidogenic region (AR) in a protein sequence plays a significant role in protein aggregation and amyloid formation. We have investigated the sequence complexity of AR that is present in intrinsically disordered human proteins. More than 80% human proteins in the disordered protein databases (DisProt+IDEAL) contained one or more ARs. With decrease of protein disorder, AR content in the protein sequence was decreased. A probability density distribution analysis and discrete analysis of AR sequences showed that ∼8% residue in a protein sequence was in AR and the region was in average 8 residues long. The residues in the AR were high in sequence complexity and it seldom overlapped with low complexity regions (LCR), which was largely abundant in disorder proteins. The sequences in the AR showed mixed conformational adaptability towards α-helix, β-sheet/strand and coil conformations.
Royal Society Open Science | 2016
Swagata Das; Supriya Das; Anupam Roy; Uttam Pal; Nakul C. Maiti
Amyloid β (Aβ) peptide is present as a major component in amyloid plaque that is one of the hallmarks of Alzheimers disease. The peptide contains a single tyrosine residue and Aβ has a major implication in the pathology of the disease progression. Current investigation revealed that the tyrosine side chain attained two different critical stereo orientations in two dissimilar conformational states of the peptide. The extended α-helical structure of the peptide observed in an apolar solvent or methanol/water mixture became disordered in aqueous medium and the radius of gyration decreased. In aqueous medium, the torsional angle around Cα–Cβ of tyrosine group became −60°. However, in its α-helical conformation in an apolar system, the measured angle was 180° and this rotameric state may be reasoned behind stronger tyrosine fluorescence compared with the disordered state of the peptide. Molecular dynamics simulation analyses and spectroscopic studies have helped us to understand the major structural changes in the secondary structure of the peptide in the two conformational states. A conformational clustering indicated that the compact state is more stable with tyrosine residue attaining the torsion angle value of −60°, whereas the native state (in HFIP/water mixture) is prevalent at a torsion angle value of −180°. High solvent accessibility has possibly stabilized the particular rotameric state (−60°) of the tyrosine residue and could be the reason behind decrease in fluorescence of the sole tyrosine residue in an aqueous buffer solution (pH 7.4) compared with its fluorescence in the α-helical structure in the micellar environment.
European Journal of Medicinal Chemistry | 2015
Biswajit Chakraborty; Debasmita Dutta; Sanjukta Mukherjee; Supriya Das; Nakul C. Maiti; Padma Das; Chinmay Chowdhury
European Journal of Medicinal Chemistry | 2014
Ranjan Preet; Biswajit Chakraborty; Sumit Siddharth; Purusottam Mohapatra; Dipon Das; Shakti Ranjan Satapathy; Supriya Das; Nakul C. Maiti; Prakas R. Maulik; Chanakya Nath Kundu; Chinmay Chowdhury
Physical Chemistry Chemical Physics | 2014
Mritunjoy Maity; Supriya Das; Nakul C. Maiti
Journal of Proteins & Proteomics | 2016
Uttam Pal; Mritunjoy Maity; Nitin Khot; Swagata Das; Supriya Das; Sandip Dolui; Nakul C. Maiti
Journal of Proteins & Proteomics | 2016
Uttam Pal; Anupam Roy; Supriya Das; Swagata Das; Mangaldeep Kundu; Khyati Bagga; Nakul C. Maiti
Journal of Physical Chemistry A | 2016
Supriya Das; Uttam Pal; Moumita Chatterjee; Sumit Kumar Pramanik; Biswadip Banerji; Nakul C. Maiti
The FASEB Journal | 2015
Nakul C. Maiti; Payel Mondal; Supriya Das