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Cyclohexadienyl dehydratase, a member of the type 2 periplasmic binding fold protein superfamily. This subfamily includes cyclohexadienyl dehydratase PheC. These proteins catalyze the decarboxylation of prephenate to phenylpyruvate in the alternative phenylalanine biosynthesis pathway in some proteobacteria and archaea. The PheC proteins belong to the PBPII superfamily of periplasmic binding proteins that differ in size and ligand specificity, but have similar tertiary structures consisting of two globular subdomains connected by a flexible hinge. They have been shown to bind their ligand in the cleft between these domains in a manner resembling a Venus flytrap. Since they the PheC proteins are so similar to periplasmic binding proteins, (PBP), it is evolutionarily plausible that several pre-existing PBP proteins might have been recruited to perform the enzymatic function.
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