pMMEc4 is a helper plasmid for enabling the repression of the PxylA promoter of a second E. coli/ Bacillus shuttle vector. pMMEc4 replicates in E. coli and carries the xylR gene under control of arabinose PBAD promoter. Description: The construction of expression vectors for Gram-positive bacteria is often done by using shuttle vectors (e.g., E. coli/ B. megaterium). Since transformation of E. coli is easy, fast, and successful it is a common host for molecular cloning. In case of genes encoding toxic products, it is essential to prevent any expression within E. coli during cloning procedures. The xylose inducible xylA / xylR induction system is not very tightly regulated in E. coli. It shows some degree of expression even without addition of an inducer. The vector pMMEc4 was constructed as a helper plasmid for preventing any expression from the xylA promoter in E. coli. It encodes for the repressor protein XylR that prevents the gene expression driven by the PxylA promoter. The expression of xylR is controlled by arabinose PBAD promoter and the AraC protein. In the presence of 0.2% arabinose, the AraC protein will bind to operator sequence that activates expression of the xylR gene, and additionally upregulate its own expression. The vector pMMEc4 carries the p15A origin of replication that is compatible with vectors from other incompatibility groups, like ColE1 group.
PEC04
* VAT and and shipping costs not included. Errors and price changes excepted
