The protein PfaD is part of four gene locus, similar to polyketide biosynthesis systems, responsible for omega-3 polyunsaturated fatty acid biosynthesis in several high pressure and/or cold-adapted bacteria. Several other members of the seed alignment for this model are found in loci presumed to act in polyketide biosyntheses per se.
Jiyao W et al.(2023). "The conserved domain database in 2023.",