L-Asparaginase from expressed in glycoswitch: effect of His-Tag fusion on the extracellular expression.

L-Asparaginase (L-ASNase) is an important enzyme used to treat acute lymphoblastic leukemia， recombinantly produced in a prokaryotic expression system. Exploration of alternatives production systems like as extracellular expression in microorganisms generally recognized as safe (such as Glycoswitch) could be advantageous， in particular， if this system is able to produce homogeneous glycosylation. Here， we evaluated extracellular expression into Glycoswitch using two different strains constructions containing the gene coding for L-ASNase (with and without His-tag)， in order to find the best system for producing the extracellular and biologically active protein. When the His-tag was absent， both cell expression and protein secretion processes were considerably improved. Three-dimensional modeling of the protein suggests that additional structures (His-tag) could adversely affect native conformation and folding from L-ASNase and therefore the expression and cell secretion of this enzyme.