Structures of open (R) and close (T) states of prephenate dehydratase (PDT)--implication of allosteric regulation by L-phenylalanine.

ABSTRACT: The enzyme prephenate dehydratase (PDT) converts prephenate to phenylpyruvate in L-phenylalanine biosynthesis. PDT is allosterically regulated by L-Phe and other amino acids. We report the first crystal structures of PDT from Staphylococcus aureus in a relaxed (R) state and PDT from Chlorobium tepidum in a tense (T) state. The two enzymes show low sequence identity (27.3%) but the same prototypic architecture and domain organization. Both enzymes are tetramers (dimer of dimers) in crystal and solution while a PDT dimer can be regarded as a basic catalytic unit. The N-terminal PDT domain consists of two similar subdomains with a cleft in between, which hosts the highly conserved active site. In one PDT dimer two clefts are aligned to form an extended active site across the dimer interface.

SUBMITTER: Tan K 

PROVIDER: S-EPMC3366492 | biostudies-literature | 2008 Apr

REPOSITORIES: biostudies-literature