Fig. 7: Synthetic receptor-based AND logic gates for signal transduction.
From: Oriented triplex DNA as a synthetic receptor for transmembrane signal transduction
a Schematic diagram illustrating the state transition of Chol3-TD. b Dissociation energy (ΔG1) of Chol3-TD with different complementary auxiliary strands Auxn (n = 9–16) and binding energy (ΔG2) for the triplex conformation, where ΔG = ΔG1 + ΔG2. c FRET emission plot showing the H+-mediated conformational change of the synthetic receptor in the presence of Auxn (n = 9–16) at pH 5.5, monitored through a pH-insensitive FRET pair (Cy3/Cy5). Inset: FRET efficiency as a function of auxiliary sequence length. Increased nucleotide count of the auxiliary sequence inhibits the conformational transformation required for the FRET process. Data are presented as mean ± s.d. (n = 3 independent samples). d Design of AND logic gates for FRET signal transduction systems using Aux16. cDNA (input 1) and H+ (input 2) were used as dual inputs to initiate transmembrane FRET (output). cDNA, 5.0 μM; H+ ions, pH 5.5. e FRET fluorescence spectroscopy under different conditions. Inset: Truth table for AND logic gates. A significant FRET output signal was detected only with the simultaneous presence of both input 1 and input 2. f Confocal fluorescence ratio images of GUVs under different conditions showing FRET signal dependent on dual input activation. Each experiment was independently repeated three times, with consistent results. g Design of AND logic gates for fluorescence catalytic signal transduction systems using Aux16. cDNA and H+ were used as dual inputs to initiate transmembrane fluorescence catalysis. cDNA, 50 μM; H+ ions, pH 5.5. h Fluorescence histogram under different conditions. Inset: Time-dependent fluorescence curve. The fluorescence catalytic signal was observed only with the simultaneous presence of both input 1 and input 2. Data in (h) are presented as mean ± s.d., two-sided Student’s t-test (n = 3 independent experiments). i Confocal fluorescence ratio images of GUVs under different conditions, showing fluorescence signals dependent on dual input activation. Each experiment was independently repeated three times, with consistent results. Scale bar (f–i), 5.0 μm. a.u. arbitrary units.
