UPF0255

Family: UPF0255

Block: X

Parent Family: No family

Comment

DUF1100 UPF0255. The family was split in two. Duf_1100-S with active site (S217 in (GXSXG) D300 H329) as in artni-Q93NG6, and Duf_1100-R (R53, D203, R 272 (in GXRXG)) as in FrsA. This family is represented by a C-C bond cleaving alpha/beta-hydrolase involved in nicotine degradation: 2,6-dihydroxy-pseudo-oxynicotine hydrolase from the nicotine-degradation pathway of Arthrobacter nicotinovorans (artni-Q93NG6) (Schleberger et al.). The fermentation/respiration switch protein FrsA (product of the yafA gene in E. Coli (ecoli-yafa)(vibvy-y856) binds the dephosphorylated form of glucose-specific enzyme IIAGl the interaction increases the glucose fermentation under oxygen-limited conditions. FrsA is a pyruvate decarboxylase (Lee et al.)(In Scop 2,6-dihydropseudooxynicotine hydrolase) Thus there are two functions and two different active sites in this family (nucleophile elbow: GXSXG in hydrolase, GXRXG in decarboxylase). However (Kellett et al.) showed Computational, structural, and kinetic evidence that Vibrio vulnificus FrsA is not a cofactor-independent pyruvate decarboxylase. The family also includes the hydrolytic polyketide shortening protein Ayg1 from fungi (Fujii et al.), and Fus2 from Gibberella species, which is part of the gene cluster that mediates the biosynthesis of the mycotoxin fusarin C. Fus2 catalyses closure of the 2-pyrrolidone ring of the intermediate 20-hydroxy-prefusarin to form another intermediate, 20-hydroxy-fusarin, which is then oxidized by Fus8 (Niehaus et al.). Other members of this family are still uncharacterised