CV-COL28a (Eq. pET-28a(+))
CV-COL28a (Eq. pET-28a(+))
CV-COL28a has a sequence identical to the pET-28a(+) expression vector. This medium-copy plasmid carries a kanamycin resistance marker and a ColE1-derived origin, and features a strong T7 promoter for high-level expression of recombinant proteins in E. coli. Its multiple cloning site provides options for introducing N- and C-terminal His·Tag® sequences, enabling flexible tagging and simplified purification of expressed proteins.
Availability: In Production
Turn Around Time : 8 days
Format: 2 tubes with 5 µg in 5 µl of TE
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Key Properties
Applications: Bacterial Expression
Copy number: Medium copy number
Expression: Constitutive
Host: E. coli
Selection markers: Kanamycin (E. coli)
Sequence: CV-COL28a_Eq._pET-28a.gb
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Background
pET-28a(+) is part of the Novagen pET expression system, a widely used platform for high-level protein expression in E. coli. Like other pET vectors, it employs a bacteriophage T7 promoter under IPTG control, but it offers additional flexibility with options for introducing N- and C-terminal His·Tag® sequences. CV-COL28a preserves the exact pET-28a(+) sequence, ensuring full compatibility with the extensive literature and experimental protocols developed around the pET system. Original documentation is available in the Novagen pET System Manual (PDF).
Features
- Antibiotic selection: Kanamycin (kan)
- Origin of replication: ColE1-derived, medium copy (~15–20/cell)
- Size: ~5.3 kb
- Promoter system: T7 promoter for high-level expression in T7 RNA polymerase–containing hosts (e.g., BL21(DE3))
- Tagging options: Multiple cloning site supports insertion with N-terminal His·Tag®, C-terminal His·Tag®, or both
- Additional features: Thrombin and enterokinase cleavage sites for tag removal
Applications
- High-level expression of recombinant proteins in E. coli
- Purification of His-tagged proteins using nickel or cobalt affinity resins
- Structural biology and enzymology studies requiring large amounts of protein
- Projects requiring flexible tag placement (N-terminal, C-terminal, or dual)
- Teaching and research with inducible bacterial expression systems
Limitations
- Requires a host strain expressing T7 RNA polymerase (e.g., BL21(DE3))
- Very high expression levels may result in insoluble proteins or inclusion bodies
- Kanamycin selection is generally more stable than ampicillin, but adds to host antibiotic load in multi-plasmid systems
- Not suitable for expression outside of E. coli