pQE-80L vector

The pQE-80L vector is a type of Escherichia coli (E. coli) expression vector. An expression vector is a type of plasmid, or circular DNA molecule, that is used to introduce specific genes into target cells. The pQE-80L vector serves as a vehicle to carry a desired genetic sequence into an E. coli cell, where the cell will use the genetic instructions to produce a particular protein. This vector operates at a low copy number, meaning there are fewer copies of the vector and its inserted gene present in the bacterial cell. As a result, protein expression from this vector tends to be lower compared to high copy number vectors. However, this might be beneficial when overexpression of the target protein might be toxic to the host cell or when wanting to control the level of target protein production. The size of the pQE-80L vector is 4752 base pairs (bp). The T5 promoter present in pQE-80L is responsible for initiating transcription, or turning on the gene, and thus protein expression. This is a strong promoter that ensures efficient and high levels of transcript production. The pQE-80L vector can be introduced into E.coli through cloning via multiple cloning sites (MCS). The MCS contains restriction enzyme sites that can be cut to allow the insertion of a target gene.