 The RluA and DRAP or deaminase domain related to riboflavin synthase have completely separate functions in the protein and it is not known whether they interact with each other.PUS 8 is necessary in yeast, but that is suspected to be related to the riboflavin synthesis and not the pseudouridine modification.PUS 9 and PUS 8 catalyze the same position in mitochondrial tRNA instead of cytoplasmic.