Generation of Transformation Competent <i>E. coli</i>

AbstractTransformation of bacterial cells, specifically Escherichia coli, is a widespread and powerful laboratory technique. This unit describes two protocols to make competent E. coli, which can then be used in subsequent transformations. The first protocol describes the preparation of chemically competent E. coli. These cells can be transformed in almost any laboratory with simple equipment, such as a water bath. The second protocol is used to make electrocompetent cells. These cells will yield high numbers of transformants, but require an electroporator, which may not be available in all environments. Thus, these two protocols should be sufficient for almost any situation that requires the preparation of competent E. coli. Curr. Protoc. Microbiol. 22:A.3L.1‐A.3L.5. © 2011 by John Wiley &amp; Sons, Inc.