For His-tagged protein production, plasmid is transformed into Escherichia coli BL21 pLysS.
xenB gene is amplified using appropriate primers with BamHI and HindIII sites and Pseudomonas putida KT2440 chromosomal DNA as a template. After digestion with restriction enzymes, the PCR product is ligated into the pET28b(+) vector. Resulting plasmid contains the coding sequence in frame with a DNA sequence encoding a His-tag, which resulted in a hexahistidine tail. For protein-His6 expression, plasmid is transformed into Escherichia coli BL21.