<p>Members of this family are photoactive yellow protein, a cytosolic, 14kDa light-sensing protein which has a 4-hydroxycinnamyl (p-coumaric acid) chromophore covalently linked to a Cys residue. The enzyme 4-coumarate--CoA ligase as described by <db_xref db="INTERPRO" dbkey="IPR012743"/> is required for its biosynthesis. The modified Cys is in a PAS domain, frequently found in signal transducing proteins. Members are known in alpha and gamma Proteobacteria that include <taxon tax_id="1061">Rhodobacter capsulatus</taxon> (Rhodopseudomonas capsulata), <taxon tax_id="1053">Halorhodospira halophila</taxon> (Ectothiorhodospira halophila), <taxon tax_id="34018">Rhodospirillum centenum</taxon> (Rhodocista centenaria), etc.</p> Photoactive yellow-protein