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Abstract

L-asparaginase has been accepted clinically as an anti-tumour agent for the effective treatment of acute lymphoblastic leukaemia and lymphosarcoma. This enzyme also possesses L-glutaminase activity and causes immunological problems. Hence, efforts have been made to develop mutants with lower or no glutaminase activity. In the present study, a homology model of L-asparaginase obtained from Pectobacterium carotovorum was docked and compared with its mutants for activities, analysed for molecular dynamics and structural stability. A total of five in-silico mutants were developed using single amino acid mutagenesis and evaluated for ligand binding for both L-asparagine and L-glutamine. One of the mutants, Y306L, showed -5.89 and -5.04 while the wild L-asparaginase revealed -5.50 and -5.12 binding energies for L-asparagine and L-glutamine, respectively. Further, substrate-enzyme interaction analysis indicated that the wild L-asparaginase showed five interactions for L-asparagine as well as for L-glutamine, whereas, the mutant, Y306L depicted eight and three interactions for L-asparagine and L-glutamine. Molecular dynamics analysis denoted that mutant protein is more stable in RMSD, RMSF and radius of gyration to that of wild-type protein. Higher binding affinity was noticed with Lasparagine and lower with L-glutamine along with higher interactions with Lasparagine and lower with L-glutamine in mutant Y306L, compared to wild Lasparaginase. This suggests that this could be a possible potential candidate for the treatment of Acute Lymphoblastic Leukaemia (ALL) with less induced side effects.

Elucidation of the Active Form and Reaction Mechanism in Human Asparaginase Type III Using Multiscale Simulations

“…However, no significant progress was observed in regard to the diminution of the immunogenetic response . In order to overcome these side effects due to the bacterial origin of the enzymes used in ALL treatments, several trials have been oriented toward their substitution by l -ASNases of mammalian origins, such as human l -ASNases (hASNaseIII) , and guinea pig ASNase (gpASNaseIII). , While several theoretical studies have been performed on the reaction mechanism of l -ASNase type I and II, − to our knowledge, no research has yet been done on the mechanism of ASNasesIII.…”