Figure 1.
a) Chemical formula of RACPPPPRSFL. A polyanionic domain (red) is connected with a thrombin-cleavable linker (PPRSFL or NleTPRSFL) (green), to a polycationic domain (blue), conjugated to Cy5. c = d-cysteine; e = d-glutamate; r = d-arginine. b) Emission spectrum of RACPPPPRSFL, measured in mouse plasma in a cuvet spectrofluorometer, before (red) and after (blue) treatment with thrombin. Before cleavage, Cy5 is quenched by Cy7, which re-emits at 780 nm. After cleavage, Cy7 no longer quenches Cy5, so the 670 nm peak from Cy5 increases and Cy7 re-emission disappears. The residual shoulder from 710 nm to 840 nm is largely from Cy5 emission.