71131  pETcoco™-1 System

The pETcoco™ System combines the advantages of T7 promoter-driven protein expression with the ability to control plasmid copy number (Sektas 2003). In the presence of 0.2% glucose, pETcoco™ recombinant plasmids are maintained at one copy per cell. In this single-copy state, pETcoco clones are extremely stable because background expression and consequent gene rearrangements or deletions are virtually absent. For plasmid preparation, the copy number can be amplified to approximately 40 copies per cell independently of target gene expression by addition of L-arabinose to the culture medium. Both target gene expression and plasmid plus insert amplification are induced upon addition of IPTG. Both pETcoco-1 and pETcoco-2 vectors feature an N-terminal His•Tag and internal S•Tag™ sequences, both of which are cleavable by enterokinase, and an optional C-terminal HSV•Tag sequence. NovaF^- Competent Cells for cloning target genes and Tuner™(DE3) Competent Cells for expression are supplied with the pETcoco-1 and pETcoco-2 Systems.



Coexpression
The pETcoco-1 plasmid contains a pET vector-compatible origin of replication and chloramphenicol resistance marker, making it suitable for transformation into cells already containing ampicillin- or kanamycin-resistant pET or pETDuet™-1 recombinants to enable the coexpression of multiple target genes in the same cell. The ampicillin-resistant pETcoco-2 plasmid is compatible with pET host strains supplying rare codon tRNAs and/or T7 lysozyme on a chloramphenicol-resistant plasmid, and with kanamycin-resistant pET recombinants for coexpression purposes. pETcoco-2 may also be used for coexpression with pACYCDuet™-1 recombinants with appropriate host strains.