(Novagen, Darmstadt, Germany). The recombinant plasmids
were then transformed into Escherichia coli JM 109 and the
accuracy of the nucleotide sequence harbored in the bacterial
clones was verified by sequencing. The plasmid DNA presenting
the correct codons was used to transform in E. coli
Rosetta-gami 2(DE3) expression host (Novagen). Protein
expression was induced by 1 mM isopropyl-b-D-thiogalactopyranoside.
Suspension of bacterial cell in a lysis buffer (50mM
Tris–HCl, pH 8.0, 5% glycerol, 50 mM NaCl, 0.5 mg/mL lysozyme)
was sonicated on ice, and the recombinant protein
fused with N utilization substance A (NusA)-tagged and 6-
Histidine (6-His)-tagged residues, and was purified using
Ni–NTA His Bind Resin (Novagen). The recombinant
MMP-like protein was separated from fusion-tagged proteins
by cleaving with recombinant enterokinase (rEK)
(Novagen) according to the manufacturer’s instructions.