Tic55 is a 55kDa LLS1-related non-heme iron oxygenase associated with protein transport through the plant inner chloroplast membrane. This domain represents the N-terminal Rieske domain of the Tic55 oxygenase alpha subunit. Tic55 is closely related to the oxygenase alpha subunits of a small subfamily of enzymes found in plants as well as oxygenic cyanobacterial photosynthesizers including LLS1 (lethal leaf spot 1, also known as PaO), Ptc52, and ACD1 (accelerated cell death 1). ROs comprise a large class of aromatic ring-hydroxylating dioxygenases that enable microorganisms to tolerate and utilize aromatic compounds for growth. The oxygenase alpha subunit contains an N-terminal Rieske domain with an [2Fe-2S] cluster and a C-terminal catalytic domain with a mononuclear Fe(II) binding site. The Rieske [2Fe-2S] cluster accepts electrons from a reductase or ferredoxin component and transfers them to the mononuclear iron for catalysis.
Jiyao W et al.(2023). "The conserved domain database in 2023.",