Stellar Competent Cells (dam–/dcm–)
An E. coli HST04 strain that lacks the genetic factors (dam and dcm) necessary for the methylation of DNA. Plasmids prepared using this product can be cut by restriction enzymes which are normally blocked by dam or dcm methylation. A dam/recA double mutation is lethal, so the parent strain is recA+. Therefore, it follows that transformation of extracellular DNA with repeat sequences can result in recombination by recA. This product is not a suitable cloning host. For transformation, it is highly recommended to use this product for constructing plasmids as mentioned above.