Phylogenetic Studies on Taurine Dioxygenase (TauD)

Taurine dioxygenase (TauD) catalyses α-ketoglutarate-dependent oxidative decomposition of taurine and is grouped into an eponymous protein family (Pfam 02668-Taurine Catabolism Dioxygenase TauD, TfdA) with other enzymes that share this domain, but differ in substrates. In this study, we have detected Low Complexity Regions (LCRs) that set TauD apart from other members of its family. Using these regions, we designed patterns that reliably give true hits when queried against UniProt. We further demonstrate the use of these LCRs in detecting horizontal gene transfer (HGT) that led to TauD incorporation in at least one fungus genome. Additionally, we studied the genomic context of tauD across bacterial species and also performed promoter analysis to gain insights into its regulation. The tauABCD operon is restricted to certain genera of class Gammaproteobacteria with few exceptions, suggesting inheritance from a common ancestor. In other classes, TauD was found to have diverse genomic neighbours. Promoter analysis reveals several global and local regulators for tauABCD operon and other operons containing tauD.