Fig. 4

Logic operations with frame-shifted λ repressor. Synthetic NOR and NAND gates are constructed with frame-shifted cI. The truth table and biochemical designs of a) NOR, c) AND and e) NAND logic gates. Experimental behaviour with logic levels for b) NOR, d) AND and f) NAND gate is also shown. Each logic gate has two inputs: IPTG and aTc and one output EGFP. The “0” and “1” inputs are basically particular concentrations of both IPTG and aTc (0 mM IPTG for IPTG “0” input, 0 ng/ml aTc for aTc “0” input, 10 mM IPTG for IPTG “1” input and 200 ng/ml aTc for aTc “1” input)