Preparation of Calcium Competent Escherichia coli and Heat-Shock Transformation

Calcium chloride heat-shock transformation is a powerful molecular biology technique used to introduce foreign DNA into a host cell. The concept of the technique is to render cells competent using CaCl2 to allow for introduction of plasmid. Plasmids usually contain the gene(s) of interest in addition to selection and/or
antibiotic resistance markers. The Hanahan or calcium chloride method is used to generate chemically competent cells. Heat-shocking facilitates the transport of plasmid into the competent cell. Transformed cells will allow for downstream applications such as plasmid amplification or protein expression. This methods
paper will outline the protocol for the preparation of calcium competent Escherichia coli using the Hanahan method and heat-shock transformation of calcium competent Escherichia coli.