<p>Phytochrome belongs to a family of plant photoreceptors that mediate physiological and developmental responses to changes in red and far-red light conditions [<cite idref="PUB00000104"/>].The protein undergoes reversible photochemical conversion between a biologically-inactive red light-absorbing form and the active far-red light-absorbing form. Phytochrome is a dimer of identical 124 kDa subunits, each of which contains a linear tetrapyrrole chromophore, covalently-attached via a Cys residue.</p><p>This domain represents a region specific to phytochrome proteins.</p> Phytochrome, central region