An efficient PCR mutagenesis strategy without gel purification [correction of "purificiation"] step that is amenable to automation

We describe here an improved megaprimer PCR mutagenesis strategy. The cumbersome gel purification step that is usually used can be omitted by appropriately cleaving the first and second DNA templates with restriction enzymes and enzymatically removing remaining primers from the first PCR reaction. We show that this improved procedure is reproducible and highly efficient. Furthermore this method is suitable for automation because all the steps are now carried out in reaction tubes.