Brevibacillus choshinensis is a Gram-positive bacterium well-suited for heterologous protein expression. The Brevibacillus expression system generates secreted target proteins efficiently (Takagi et al. 1989) and are ideal for eukaryotic recombinant protein expression, resulting in a high yield of active protein. The Brevibacillus system is also almost completely free of proteases, allowing for the production of intact protein products. Our BIC system involves transfecting in a linear plasmid with a PCR insert and relying on the bacteria to recombine into an expression vector, while the Brevibacillus Expression System II involves first cloning the shuttle vector in E. coli and then transfecting in the complete expression vector.

The Brevibacillus system facilitates disulfide-bond formation, which isoften requiredfor activity in proteins of eukaryotic origin. In addition, B. choshinensis serves as an excellent host for intracellular protein production, producing soluble intracellular proteins in the cytoplasm without the formation ofinclusion bodies. In fact, Brevibacillus expression systems often work better than comparableE. coli-based systemsfor the expression ofcertain recombinant protein targets.

Use of his-tag vectors (pNC-HisE, pNC-HisF, pNC-HisT, pNI-His) allowsfor quick andeasypurification of the expressed target proteins. These tags can be removed by protease treatment following purification.