<p>This domain is found in bacterial and plant proteins to the C terminus of a Rieske 2Fe-2S domain (<db_xref db="INTERPRO" dbkey="IPR005806"/>). One of the proteins the domain is found in is Pheophorbide a oxygenase (PaO) which seems to be a key regulator of chlorophyll catabolism. Arabidopsis PaO (AtPaO) is a Rieske-type 2Fe-2S enzyme that is identical to Arabidopsis accelerated cell death 1 and homologous to lethal leaf spot 1 (LLS1) of maize [<cite idref="PUB00020931"/>], in which the domain described here is also found. </p>