A mutant of the phototoxic protein KillerRed that does not form DsRed-like chromophore

Gorbachev DA, Sarkisyan KS
About authors

Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Moscow, Russia

Correspondence should be addressed: Karen S. Sarkisyan
Miklukho-Maklaya, 16/10, of. 34/632, Moscow, 117997; moc.liamg@naysikras.s.nerak

About paper

Funding: this work would not have been published without the generous support and the strict publication requirements of the Russian Foundation for Basic Research grant 18-04-01173. KSS is supported by the president fellowship 075-15-2019-411. Experiments were partially carried out using the equipment provided by the Institute of Bioorganic Chemistry of the Russian Academy of Sciences Сore Facility (CKP IBCH; supported by Russian Ministry of Education and Science Grant RFMEFI62117X0018).

Acknowledgements: we thank to the Center for Precision Genome Editing and Genetic. Technologies for Biomedicine (Moscow) for the genetic research methods.

Author contribution: Sarkisyan KS, Gorbachev DA — conceived and planned the project, performed the experiments, analysed data and prepared the manuscript.

Received: 2019-12-08 Accepted: 2019-12-18 Published online: 2019-12-20

Genetically encodable photosensitizers based on fluorescent proteins produce reactive oxygen species when illuminated with light. Although widely used as optogenetic tools, existing photosensitizers with green fluorescence possess suboptimal properties motivating for a search of new protein variants with efficient chromophore maturation and high phototoxicity. Here we report a mutant of the phototoxic fluorescent protein KillerRed protein with fluorescence in the green part of the spectrum. The mutant variant carries mutations I64L, D114G, and T115S and does not form a DsRed-like chromophore. The protein can be used as a template to create new genetically encodable photosensitizers that are spectrally different from KillerRed.

Keywords: photosensitizer, fluorescent protein, KillerRed, mutagenesis, hypsochromic shift, optogenetics