• Ashutosh Kumar

      Articles written in Journal of Chemical Sciences

    • NMR of unfolded proteins

      Amarnath Chatterjee Ashutosh Kumar Jeetender Chugh Sudha Srivastava Neel S Bhavesh Ramakrishna V Hosur

      More Details Abstract Fulltext PDF

      In the post-genomic era, as more and more genome sequences are becoming known and hectic efforts are underway to decode the information content in them, it is becoming increasingly evident that flexibility in proteins plays a crucial role in many of the biological functions. Many proteins have intrinsic disorder either wholly or in specific regions. It appears that this disorder may be important for regulatory functions of the proteins, on the one hand, and may help in directing the folding process to reach the compact native state, on the other. Nuclear magnetic resonance (NMR) has over the last two decades emerged as the sole, most powerful technique to help characterize these disordered protein systems. In this review, we first discuss the significance of disorder in proteins and then describe the recent developments in NMR methods for their characterization. A brief description of the results obtained on several disordered proteins is presented at the end.

    • Synthesis, characterization and photophysical studies of the flavopeptide conjugates as model for the covalently linked flavoenzymes

      M S S Vinod Mouli Ashutosh Kumar Mishra

      More Details Abstract Fulltext PDF

      Here, we have demonstrated an easy and efficient synthetic route for the synthesis of the flavo-peptide conjugates as model for the naturally occurring covalently linked flavoenzymes. A judicially functionalized flavin analogue was used for the coupling reaction with the pre-synthesized peptidic motifs using solution-phase chemistry. Representative examples using mono-, di- and tripeptides were reported to couple with the C7-position of the flavin moiety to showcase the generic nature of the synthetic strategy. Further photophysical investigation including quantum yield measurements, concentration-dependent studies and fluorescence quenching experiments reveal the intramolecular nature of the charge transport process in cases where tyrosine is present, similar to that found in the natural counterpart.

      This manuscript discusses a simple/efficient approach for the synthesis of flavopeptide conjugates as a true model for covalently-liked-flavoenzymes. Coupling reaction between the suitably functionalized flavin moiety and the pre-synthesized peptide entities was envisaged and undertaken to prove the generality of the approach. Further photophysical investigation including quantum yield measurements, concentration-dependent studies and fluorescence quenching experiments reveal the intramolecular nature of the charge transport process in cases where tyrosine is present, similar to that found in the natural counterpart. Such a synthetic flavopeptide model may provide a further investigation to provide an insight into the corresponding biological phenomenon.

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