Porcine β-defensin-2 (pBD2) is a cationic antimicrobial peptide that has therapeutic potential. The amount of pBD2 in nature is limited, and the expression of pBD2 in Escherichia coli is low, probably because a different gene codon is used by prokaryotic organisms to that used by eukaryotes. Codon preference optimization is one of the ways to increase heterologous expression of pBD2. To achieve...

The biosynthesis of carboxylic acids including fatty acids from biomass is central in envisaged biorefinery concepts. The productivities are often, however, low due to product toxicity that hamper whole-cell biocatalyst performance. Here, we have investigated factors that influence the tolerance of Escherichia coli to medium chain carboxylic acid (i.e., n-heptanoic acid)-induced stress. The met...

Recombinant His-tagged proteins expressed in Escherichia coli and purified by immobilized metal affinity chromatography (IMAC) are commonly coeluted with native E. coli proteins, especially if the recombinant protein is expressed at a low level. The E. coli contaminants display high affinity to divalent nickel or cobalt ions, mainly due to the presence of clustered histidine residues or biologi...

A uracil-DNA glycosylase gene was cloned from Chlamydia pneumoniae AR39 and expressed in E. coli strains BL21 (DE3) and BL21 (DE3) pLysS. After purification by Ni-NTA His x Bind Resin and DEAE Sepharose Fast Flow column chromatography, recombinant CpUDG with a specific activity of 1,000,000 U/mg was obtained. The enzymatic activity of the purified CpUDG protein was further characterized using o...

A cryopreservation condition for D-amino acid oxidase (DAAO)-overexpressing Escherichia coli (E. coli BL21(DE3)/pET-DAAO) was established. Ten percent was the optimum concentration of glycerol as a cryoprotectant, and its diffusion into stationary phase cells was superior to that into log cells. The results also showed that rather than fast cooling, a slow cooling method was appropriate to our ...

Elaboration of different toxins by enterotoxigenic E. coli has been considered as one of the main virulence factors contributing to the manifestation of disease caused by these microorganisms. Various strategies have been employed to raise antibodies against these toxins as a line of defense. In this study, the 3’ terminus of the gene that codes for the binding subunit of the heat-labile entero...

Fragment C is the C-terminal domain of the heavy chain of tetanus toxin that can promote the immune response against the lethal dose of this toxin. Therefore, this portion can be considered as a candidate vaccine against tetanus infection, which occurs by Clostridium tetani. The present study aimed to compare the expression of tetanus toxin fragment C in Escherichia coli  BL21 (DE3) pLysS cells...

Membrane protein production is usually toxic to E. coli. However, using genetic screens strains can be isolated in which the toxicity of membrane protein production is reduced, thereby improving production yields. Best known examples are the C41(DE3) and C43(DE3) strains, which are both derived from the T7 RNA polymerase (P)-based BL21(DE3) protein production strain. In C41(DE3) and C43(DE3) mu...