The effect of the crp genotypes on the transformation efficiency in Escherichia coli.

We have found that a significant difference exists in transformation efficiency between the crp+/crp- isogenic pair of strains of Escherichia coli, with the efficiency being much higher in crp- than in crp+. The ratio of transformation efficiency between crp+ and crp- strains depends very little on the plasmid size. This observation suggests that the difference of the transformation efficiency is due to mechanisms other than a crp-regulated endonuclease. The crp gene is one of the first specific genes that have been shown to affect transformation efficiency.