Study of two light-sensitive proteins in Ostreococcus tauri sheds light on how cryptochromes evolved

Five genes of the Cry/photolyase family were identified in two green algae of the Ostreococcus genus.

• Three sequences were assigned to cyclobutane pyrimidine dimer (CPD) photolyases, one to a DASH-type Cry, and another showed high homology with the diatom CPF1.
• Both purified OtCPF1 and OtCPF2 proteins bind non-covalently to flavin adenine dinucleotide (FAD), with OtCPF2 also binding to 5,10-methenyl-tetrahydrofolate (MTHF).
• All five CPF members of Ostreococcus tauri are regulated by light.
• OtCPF1 and OtCPF2 exhibit photolyase activity.
• OtCPF1 interacts with the CLOCK:BMAL heterodimer, which regulates circadian clock function in other organisms.
• Evidence suggests OtCPF1 is involved in maintaining the Ostreococcus circadian clock.

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