UASt regulatory sequences drive expression of an optimized version of Ecol\dam; in addition to codon optimization, it contains a L122A mutation and cryptic splicing regulatory sites have been removed (PMID:27707796). The L122A mutation has been shown to increase the specificity of methylation on the GATC target site, due to a loss of ability to methylate noncanonical near-cognate sites (PMID:15882618).