Maps and sequence overview of pTX8048 and pTX8049. (A) Vector maps of pTX8048 and pTX8049, which were constructed by insertion of the E. coli thioredoxin gene trxA, an enterokinase-specific cleavage site and a hexahistidine-tag as illustrated; (B) DNA sequence overview of the multiple cloning sites of pTX8048 and pTX8049. PnisA, nisin-inducible promoter; RBS, ribosome binding site; trxA, E. coli thioredoxin A-encoding gene; MCS, multiple cloning site; term, transcriptional terminator; Cm, chloramphenicol cassette. All restriction sites shown here are unique and can be used as cloning sites. The restriction site BamHI in pTX8048 and pTX8049 allows the in-frame cloning of the gene of interest.