Flavodi-iron proteins (FLV) activity is important to reduce photodamage, but it also creates a futile cycle when electrons from water are donated back to oxygen. Furthermore, FLV is potentially competing with carbon fixation for reducing power, and thus, if constitutively active, it would reduce photosynthetic efficiency. To maximize its positive impact on productivity, thus FLV should be active only when needed. Indeed, in organisms that natively express them, FLV acts as an electron acceptor only for a limited time frame, but the molecular mechanism at the base of this regulation is unknown. Therefore, responding to how FLV is regulated is essential for understanding its biological role and introducing the protein in crops. Hence, information on 3D protein structure will be precious to identify residues targeted by mutagenesis analysis to generate protein variants with altered regulation by targeting substrate binding sites and conserved Cysteines.