L-asparaginase (L-ASN) is an anti-cancer enzyme therapeutic drug that exerts cytotoxicity via inhibition of protein synthesis through depletion of L-asparagine in the tumour microenvironment. The therapeutic performance of the native drug is partial due to the associated instability, reduced half-life and immunogenic complications. In this study, we report the modification of recombinant L-asparaginase with PEG and an integrated computational strategy to probe the PEGylation in the protein to understand the biological stability/activity imparted by PEG. PEGylation of L-asparaginase resulted in enhanced thermal and pH activities with extended serum half-life and resistance to proteases compared to the native enzyme. The molecular dynamics analysis revealed intricate interactions required in the coupling of PEG to L-asparaginase to bestow stronger binding affinity of L-asparagine moiety towards L-asparaginase. PEG-asparagine complex ensured stable conformation over both the native protein and asparagine-protein complex thus elucidating the PEG-induced stable conformation in the protein. PEG mechanistically stabilized L-asparaginase through inducing pocket modification at the receptor to adapt to the cavity. Thus, the study provides the rationale of PEGylation in imparting the stability towards L-asparaginase which would expand the potential application of L-asparaginase enzyme for the effective treatment of cancer.
Keywords: L-asparaginase, Polyethylene glycation, biological stability, computation.
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