Bacterial expression vectors are used to introduce foreign genetic material into a host in order to replicate and amplify the foreign DNA sequences as a recombinant molecule.
The broad portfolio provided by Sigma-Aldrich solves your bacterial expression vector challenge by organizing the different formats into easy to use selection guides for your convenience.
Sigma-Aldrich provides bacterial expression vectors that utilize tac promoter-based vectors, which allow expression, detection, and purification of recombinant FLAG® and MAT (Metal Affinity Tag) fusions in E. coli. These vectors offer a choice of periplasmic (+ompA) or cytoplasmic expression of amino or carboxy-terminal tagged fusions. tac expression vectors confer ampicillin resistance for easy selection of positive transformants. Additionally, the vectors contain the T1T2 transcriptional terminator, pMB1 (derivative of pBR322) origin of replication, the f1 origin, and the lacI gene for repression of the tac promoter. These vectors can be used to express protein in any established E. coli expression host.
Also offered are T7 promoter-based bacterial expression vectors, which allow for expression, detection and purification of recombinant FLAG and MAT (Metal Affinity Tag) fusions in E. coli. Several vectors containing the T7 promoter offer dual tag options for FLAG and MAT-tagged fusion proteins. These vectors confer ampicillin resistance for easy selection of positive transformants.
pT7-FLAG and pT7-MAT vectors offer the very strong T7/lac promoter. These bacterial expression vectors produce even higher yields of recombinant protein than the tac promoter system. However, the T7 promoter is known for background ("leaky") expression, which can be a drawback when recombinant proteins are toxic to the host cell. Therefore, Sigma-Aldrich vectors contain the lac operator (lacO) sequences immediately downstream from the promoter to reduce leaky expression. Unlike the tac promoter system, pT7 vectors must be expressed in hosts containing a source of the T7 polymerase such as (DE3) lysogenic strains.