The molecular mechanism of light-induced bond formation and breakage in the cyanobacteriochrome TePixJ.

Cyanobacteriochromes (CBCRs) are small and versatile photoreceptor proteins with high potential for biotechnological applications. Among them, the so-called DXCF-CBCRs exhibit an intricate secondary photochemistry: miliseconds after activation with light, a covalent linkage between a conserved cysteine residue and the light-absorbing tetrapyrrole chromophore is reversibly formed or broken. We employed time-resolved IR spectroscopy over ten orders of magnitude in time in conjunction with 2D-IR spectroscopy to investigate the molecular mechanism of this intriguing reaction in the DXCF-CBCR model system TePixJ from .