Molecular characteristics of InlB protein of Listeria monocytogenes wild strain and it's expression and purification

Abstract:

Internalin B of Listeria monocytogenes TA wild strain was amplified by PCR method and sequenced, then subcloned into prokaryotic vector pET28a for expression. The complete length of InlB gene was 1893 bp, encoding 630 amino acids. The front 35 amino acids consisted of signal peptide. There were one cap domain with α-helix region, 6 leucine-rich repeat motifs, one immunoglobulin (Ig)-like domain, one B repeat sequence, 3 direct repeat GW domains and 5 N-glycosylation sites. The amino acid of leucine amounted to 10.2 percent in all amino acids of deduced sequence. Compared the InlB genes with that of other 18 isolates reported in GenBank, the identities of nucleotide sequence and deduced amino acid sequence were 91.1%～99.6% and 92.3%～99.8%, respectively. Expressed InlB protein was detected by SDS-PAGE and confirmed by western blot. Recombinant protein was successfully purified by Ni2+ affinity chromatograph column.