Site-Specific Photoinduced Dynamics of the LOV Protein EL222 Monitored by Multiple Genetically Encoded Infrared Probes

Abstract

Proteins containing the light-oxygen-voltage (LOV) domain are photosensory receptors that mediate biological actions in response to blue light. For instance, the bacterial transcription factor EL222 regulates gene expression in a light-regulated manner and has found use in optogenetic applications. Upon excitation of the embedded flavin mononucleotide (FMN) cofactor, EL222 undergoes structural changes that ultimately drive its association with DNA. However, our knowledge of the light-adapted state(s) and the molecular mechanism underlying the transition between dark and lit states is incomplete.