[Expression and characterization of a new class IIa bacteriocin].

NB-Cl gene is a potential class IIa bacteriocin gene. To obtain its soluble expression, NB-C1 was fused with the green fluorescent protein (GFP) gene and a recombinant expression vector plVEX 2.4d-GFP-NB-C1 was constructed, which was transformed into Escherichia coli BL21(DE3) pLysS. The expressed fusion protein GFP-NB-CI was purified by Ni-NTA affinity chromatography and the bioactivity was examined using Listeria monocytogenes as the indicator bacteria. The results showed that the expressed fusion protein GFP-NB-C1 was soluble and the final concentration of the purified fusion protein was 36.1 mg/L E. coli culture and had the purity above 95%. The antimicrobial assay of GFP-NB-C1 was analyzed and showed its high activity against Listeria monocytogenes.