This protein family is found in fungi and bacteria, including the alpha subunit of an haem-dependent oxidative N-demethylase (HODM) from Pseudomonas mendocina. This protein, catalytically active, is responsible for haem, oxygen and NADPH-dependent dimethylamine (DMA) binding. It shows structural similarity to the to the Aer2 PAS domain, but lacks the core PAS-domain alpha-helix that forms the Aer2 haem pocket, and displays extended beta-strands and a longer loop. The structure of Ectopseudomonas mendocina Heme-dependent oxidative N-demethylase alpha subunit, PDBe:5lte, shows that it is an haem-binding PAS domain, similar in structure to PAS gas sensors.