KillerOrange, a Genetically Encoded Photosensitizer Activated by Blue and Green Light

PLoS One. 2015 Dec 17;10(12):e0145287. doi: 10.1371/journal.pone.0145287. eCollection 2015.


Genetically encoded photosensitizers, proteins that produce reactive oxygen species when illuminated with visible light, are increasingly used as optogenetic tools. Their applications range from ablation of specific cell populations to precise optical inactivation of cellular proteins. Here, we report an orange mutant of red fluorescent protein KillerRed that becomes toxic when illuminated with blue or green light. This new protein, KillerOrange, carries a tryptophan-based chromophore that is novel for photosensitizers. We show that KillerOrange can be used simultaneously and independently from KillerRed in both bacterial and mammalian cells offering chromatic orthogonality for light-activated toxicity.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Green Fluorescent Proteins / chemistry*
  • Green Fluorescent Proteins / genetics
  • HEK293 Cells
  • Humans
  • Luminescent Proteins / chemistry*
  • Luminescent Proteins / genetics
  • Luminescent Proteins / radiation effects
  • Luminescent Proteins / toxicity
  • Photosensitizing Agents / chemistry*
  • Photosensitizing Agents / radiation effects
  • Photosensitizing Agents / toxicity
  • Red Fluorescent Protein
  • Ultraviolet Rays


  • Luminescent Proteins
  • Photosensitizing Agents
  • killer red protein, Anthomedusae
  • Green Fluorescent Proteins

Grants and funding

The work was supported by Russian Science Foundation (14-25-00129). KSS was supported by OPTEC grant for young scientists (21/2014/51-Msk) and Science and Innovation Youth Contest Participant grant (UMNIK, 3616ГУ2/2014). Experiments were partially carried out using the equipment provided by the IBCH сore facility (CKP IBCH). KMS acknowledges generous support from the National Science Foundation (CHE-1213047).