This very small protein (about 46 amino acids) consists largely of a single predicted membrane-spanning region. It is found in Photobacterium profundum SS9 and in three species of Vibrio, always near periplasmic nitrate reductase genes, but far from the periplasmic nitrate reductase genes in Aeromonas hydrophila ATCC 7966.
Jiyao W et al.(2023). "The conserved domain database in 2023.",