pSF-OXB1 (OG553) Weak Strength Bacterial Promoter Plasmid

Product Code: OG553R1
Product Code: OG553C1
Product Code: OG553G1

Product Description

Bacterial constiutive expression plasmid containing the OXB1 weak promoter (weaker than OXB11). Developed by modifying the AraBAD E.coli promoter.

Plasmid Information

Product Name: pSF-OXB1

Product Code: OG553

Size (bp): 3859 bp

Bacterial Antibiotic Selection: KanR

Origin and Compatibility: pUC high copy derived from pBR322

Bacterial Copy Number: 500-700 per cell

Promoter: OXB1 weak bacterial promoter

Plasmid Purpose:

This plasmid contains a weak bacterial promoter for expression in E.coli. It has been derived by modifying the AraBAD (arabinose operon) promoter to remove the AraC repressor site. When tested this promoter was found to be very weak in comparison to most other bacterial promoters including those in our product range. For this reason the promoter is called OXB1 in our collection of bacterial promoters that extend from OXB1 to OXB20 with OXB20 being the strongest. These promoters do not require induction for expression.

Promoter Expression Level:

This plasmid contains a weak constitutive E.coli promoter that was derived from the Arabinose operon. It is part of our constitutive bacterial promoter range. This promoter (OXB1) shows the lowest level of expression in the range with OXB20 showing the highest level of expression. They require no inducing agent for expression.

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Transcription Termination:

This plasmid contains three alternative transcription terminators for mammalian bacterial and bacteriophage (T7) expression. This means that only the promoter needs to be changed to alter the expression system you are using. We sell multiple promoters that can be used in each of these systems. The presence of each terminator does not reduce expression in the alternative systems.

Cloning in a Gene:

This plasmid has been designed to be compatible with a range of cloning techniques. The multiple cloning site contains a range of standard commonly used restriction sites for cloning. Using these sites genes can be inserted using standard cloning methods with DNA ligase. Other methods such as ligase independent cloning (LIC) Gibson Assembly InFusionHD or Seamless GeneArt can also be used and because all of our plasmids are based on the same backbone the same method can be used for cloning into all of our catalogue vectors.

Multiple cloning site notes:

There are a few important sites within the MCS. These include the NcoI site the XbaI site and the BsgI and BseRI sites. The NcoI site contains a start codon that is immediately downstream of both a Kozak and Shine-Dalgarno ribosomal binding site. These allow for optimal positioning of genes when the start codon is placed in this location. If this is not required and you wish to use a downstream site for gene cloning you can remove the NcoI site by cleaving the plasmid with KpnI.

The XbaI site contains a stop codon. This stop codon is positioned in a specific position in relation to the BsgI and BseRI sites that are immediately downstream. When either BseRI or BsgI cleave the plasmid they produce a TA overhang from the stop codon in the XbaI site that is compatible with all of our peptide tag plasmids cut with the same sites. BseRI and BsgI sites are non-palindromic and cleave a defined number of bases away from their binding site.

Whenever we clone a gene into our multiple cloning site we always position the start and stop codon in the same positions in the MCS. If the start and ends of the genes are not compatible with NcoI and XbaI we extend the sequence to the nearest external sites but keep the start and stop codons locations consistent.

Intellectual Property Status

This product is part of our SnapFastâ„¢ plasmid range, for more information on the intellectual property status of this plasmid please click here. For more information on the terms of our licences please click here.