Figure 2: Spatially segregated reaction sequences in multi-compartment vesicles.

(a) Multi-step enzymatic pathway scheme (b-d) Schematic of the three vesicle systems that were generated, together with fluorescence and composite images of representative vesicles at the start and at the end of the reaction. Brightness and contrasts enhanced equally across all images. Scale bar, 250 μm. Graphs showing fluorescence intensity of the Amplex Red-containing compartment show the dye being oxidized to fluorescent resorufin as the reaction proceeds. (b) Glucose is oxidized, producing hydrogen peroxide, which translocates through the bilayer to initiate the oxidation of Amplex Red. (c) Glucose diffuses in from the exterior, through α-HL pores, to initiate subsequent reaction steps. This represents a simple sense/response network. (d) The full three-step reaction cascade where each step is isolated in a single compartment. Lactose is first hydrolysed to glucose, which then translocates through the bilayer to initiate subsequent steps as before. Error bars represent 1 s.d. (n=4).