Cloning rbsB gene from Vibrio harveyi and its expression

Vibrio harveyi is one of the most important mariculture pathogens. We amplified the whole rbsB gene (GenBank ID MF797015) sequence of V.harveyi strain 354 which was predicted to encode 292 amino acid with molecular weight of 30.7 kD, isoelectric point of 5.05 and hydrophilic coefficient of 0.043. Thus, the Vh-RbsB may be a hydrophobic protein. Phylogenetic tree constructed based on RbsB amino acid sequence indicates that Vh-RbsB has the closest relationship with V.owensii CAIM 1854. A recombinant plasmid pGEX-4t-1-rbsB was constructed and transformed into Escherichia coli BL21 (DE3). The relative molecular weight of the recombinant protein was about 59 kD. The highest expression was observed at 37 ℃, 8 h, concentration of IPTG of 0.6 mmol·L^–1.