KillerRed photosensitizer protein (KillerRed) (KillerRed)

KillerRed is a genetically encoded red fluorescent protein, originally derived from the chromoprotein anCP of the jellyfish Anemonia sulcata, that functions as a potent photosensitizer (Bulina et al., 2006, Nature Biotechnology). Unlike standard fluorescent proteins like GFP, which are optimized for low phototoxicity, KillerRed is engineered to efficiently generate reactive oxygen species (ROS), specifically superoxide radicals, upon irradiation with green light (~540-580 nm) (Vegh et al., 2011, Chemical Communications). This light-induced ROS production facilitates the targeted destruction of cells or the specific inactivation of fusion proteins through a process known as chromophore-assisted light inactivation (CALI) (Carpentier et al., 2009, FEBS Letters). Structurally, KillerRed is a dimeric protein containing a Gln65-Tyr66-Gly67 chromophore that is accessible to water and oxygen, a feature that promotes its phototoxic efficiency (Carpentier et al., 2009, FEBS Letters). While primarily used as a research tool in optogenetics and cell biology, it has been explored for potential applications in photodynamic therapy (PDT) to induce localized apoptosis in cancer cells (Bulina et al., 2006, Nature Biotechnology). The protein's ability to be expressed in specific intracellular compartments or fused to specific proteins allows for unprecedented spatial control over oxidative stress (Vegh et al., 2011, Chemical Communications).

Other names

KillerRedKRPhotosensitizing red fluorescent proteinanCP-derived photosensitizer

KillerRed acts as a Type I photosensitizer; upon excitation with green light, its chromophore reacts with molecular oxygen to generate superoxide radicals, leading to localized oxidative damage and cell death (Bulina et al., 2006, Nature Biotechnology).