phosphoserine phosphatase/homoserine phosphotransferase bifunctional protein
This protein is has been characterized as both a phosphoserine phosphatase and a phosphoserine:homoserine phosphotransferase. In Pseudomonas aeruginosa, where the characterization was done, a second phosphoserine phosphatase (SerB) and a second homoserine kinase (thrB) are found, but in Fibrobacter succinogenes neither are present. This enzyme is a member of the haloacid dehalogenase (HAD) superfamily, specifically part of subfamily IB by virtue of the presence of an alpha helical domain in between motifs I and II of the HAD domain. The closest homologs to this family are monofunctional phosphoserine phosphatases (TIGR00338).