Structural domains comprising this superfamily share the structure of a novel class of D-serine dehydratase, a zinc dependent enzyme involved in the degradation of D-serine, a physiological co-agonist of the NMDA receptor which is thus involved in the regulation of excitatory neurotransmission, important for higher brain functions in vertebrates. The primary structure of the enzyme shows significant similarities to that of metal-activated D-threonine aldolases, fold-type III pyridoxal 5'-phosphate (PLP)-dependent enzymes PMID:21676877, PMID:25715785.