The constructed plasmids and designed synthetic RDS sequences. (A) Schematic of the plasmid harboring the luxR gene with the designed RDS sequences. Based on a genetic algorithm, the 10 nucleotides upstream of the start codon were modified to create synthetic RDS sequences with specific translational efficiencies. For measurement of LuxR protein expression, the lacZα gene was fused to the luxR gene. (B) The designed synthetic RDS sequences are listed; the RRS sequences are indicated in bold. For sRDS21 and 22 they have the same designed spacer sequence but their SD sequences were modified further.