A potential type-II L-asparaginase from marine isolate Bacillus australimaris NJB19: Statistical optimization, in silico analysis and structural modeling.

Abstract

L-asparaginase is a cardinal biotherapeutic drug for treating acute lymphoblastic leukemia, which is highly prevalent in children worldwide. In the current investigation, L-asparaginase producing marine bacterial isolate, Bacillus australimaris NJB19 (MG734654), was observed to be producing extracellular glutaminase free L-asparaginase (13.27 ± 0.4 IU mL-1). Production of L-asparaginase was enhanced by the Box-Behnken design approach that enumerated the significant variables affecting the enzyme production. The optimum levels of the derived variables resulted in 2.8-fold higher levels of the enzyme production (37.93 ± 1.06 IU mL-1). An 1146 bp L-asparaginase biosynthetic gene of Bacillus australimaris NJB19 was identified and cloned in E. coli DH5α, fused with a histidine tag. The in silico analysis of the protein sequence revealed the presence of a signal peptide and classified it as a type II L-asparaginase. Toxic peptide prediction disclosed no toxin domain in the protein sequence, hence suggesting it as a non-toxic protein. The secondary structure analysis of the enzyme displayed a comparable percentage of alpha-helical and random coil structure, while 14.39% and 6.57% of amino acid residues were composed of extended strands and beta-turns, respectively. The functional sites in the three-dimensional structural model of the protein were predicted and interestingly had a few less conserved residues. Bacillus australimaris NJB19 identified in this study produces type-II L-asparaginase, known for its high affinity for asparagine and effectiveness against leukemic cells. Hence, these observations indicate the L-asparaginase, thus obtained, as a potentially significant and novel therapeutic drug.

• Authors: Namrata Chakravarty, Priyanka, Jyoti Singh, R P Singh
• Journal: International journal of biological macromolecules (Int J Biol Macromol) Vol. 174 Pg. 527-539 (Mar 31 2021) ISSN: 1879-0003 [Electronic] Netherlands
• PMID: 33508362 (Publication Type: Journal Article)
• Copyright: Copyright © 2021 Elsevier B.V. All rights reserved.

Chemical References

• Bacterial Proteins
• Recombinant Proteins
• Asparagine
• Asparaginase

Topics

• Amino Acid Sequence
• Asparaginase (chemistry, genetics, metabolism)
• Asparagine (metabolism)
• Bacillus (classification, enzymology, genetics, isolation & purification)
• Bacterial Proteins (chemistry, genetics, metabolism)
• Cloning, Molecular (methods)
• Computer Simulation
• Escherichia coli (genetics, growth & development)
• Geologic Sediments (microbiology)
• Models, Molecular
• Phylogeny
• Protein Structure, Secondary
• Recombinant Proteins (chemistry, metabolism)