Biliverdin - in Fluorescence Imaging

In Fluorescence Imaging

In a complex with reengineered bacterial phytochrome, biliverdin has been employed as IR-emitting chromophore for in vivo imaging. In contrast to fluorescent proteins which form their chromophore through posttranslational modifications of the polypeptide chain, phytochromes bind an external ligand (in this case, biliverdin), and successful imaging of the first bacteriophytochrome-based probe required addition of the exogenous biliverdin. Recent studies demonstrated that bacteriophytochrome-based fluorescent proteins with high affinity to the biliverdin can be imaged in vivo utilizing endogenous ligand only and, thus, with the same easiness as the conventional fluorescent proteins. Advent of the second and further generations of the biliverdin-binding bacteriophytochrome-based probes should broaden possibilities of the non-invasive in vivo imaging.