9BAD

Crystal structure of Bacillus subtilis 168 L-asparaginase II with antileukemic activity

Summary for 9BAD

• Entry DOI: 10.2210/pdb9bad/pdb
• Descriptor: L-asparaginase 2, SODIUM ION, GLYCEROL, ... (4 entities in total)
• Functional Keywords: enzyme, leukemia, recombinant, antitumor protein
• Biological source: Bacillus subtilis subsp. subtilis str. 168
• Total number of polymer chains: 4
• Total formula weight: 160000.62

Authors

Gomes, J.G.S.,Rocha, B.A.M.,Brandao, L.C.,Furtado, G.P.,Pontes, L.Q.,Lourenzoni, M.R. (deposition date: 2024-04-03, release date: 2025-10-08, Last modification date: 2025-11-26)

Primary citation

Brandao, L.C.,da Silva Gomes, J.G.,Pinheiro, D.P.,Caetano, L.F.,Bezerra, M.R.L.,Pontes, L.Q.,Pinheiro, M.P.,de Aquino, A.V.F.G.,Silva, J.M.F.,Souza, P.F.N.,Furtado, C.L.M.,Pessoa, C.,Lourenzoni, M.R.,da Rocha, B.A.M.,Furtado, G.P.
Structural and biochemical characterization of a thermostable Bacillus subtilis L-asparaginase with antiproliferative effects on hematological cancer cell lines.
Int.J.Biol.Macromol., 333:148804-148804, 2025

PubMed Abstract: L-asparaginase catalyzes the hydrolysis of L-asparagine into aspartic acid and ammonia and is found in animals, plants, and microorganisms. Microbial sources are preferred for large-scale production due to their efficiency and ease of cultivation. In this study, we produced and characterized a recombinant L-asparaginase from Bacillus subtilis (Asp-Z). Asp-Z was heterologously expressed in Escherichia coli and purified by affinity chromatography, yielding soluble protein with optimal activity at 55 °C and pH 7.5. The kinetic parameters under these conditions were a Km of 0.47 mM and a Vmax of 52.13 U/mg. Asp-Z was specific for L-asparagine, showing no detectable glutaminase activity, and exhibited antiproliferative effects against hematological cancer cell lines, particularly RAJI and JURKAT, with IC₅₀ values in the micromolar range. In silico analysis revealed distinct immunogenic epitopes between Asp-Z and the commercial E. coli L-asparaginase, suggesting divergent antigenic profiles, whereas crystallographic data revealed a conserved tetrameric fold with a highly flexible active-site loop. Together, these findings highlight Asp-Z as a thermostable, glutaminase-free, and poorly immunogenic enzyme that represents a promising scaffold for optimization through protein engineering toward therapeutic and biotechnological applications.

PubMed: 41203148
DOI: 10.1016/j.ijbiomac.2025.148804

Experimental method

X-RAY DIFFRACTION (1.3 Å)