Functional dynamics of the photoactivated adenylate cyclase OaPAC revealed by fluorescence spectroscopy and small-angle X-ray scattering

OaPAC is a photoactivated adenylate cyclase (PAC) from the photosynthetic cyanobacterium Oscillatoria acuminata and belongs to a class of photoactive flavoenzymes which are involved in the conversion of ATP (adenosine triphosphate) to the important second messenger cAMP (cyclic adenosine monophosphate). The photoactivation is controlled by a BLUF (Blue Light Sensing Using Flavin) domain; a well-known light-triggered switch present in many biological photoreceptors and able to control photochemical energy into a diverse set of cellular responses (e.g.