title: Identification of a small protein domain present in all plant lineages that confers high prephenate dehydratase activity.
abstract: l-Phenylalanine serves as a building block for the biosynthesis of proteins, but also as a precursor for a wide range of plant-derived compounds essential for plants and animals. Plants can synthesize Phe within the plastids using arogenate as a precursor; however, an alternative pathway using phenylpyruvate as an intermediate, described for most microorganisms, has recently been proposed. The functionality of this pathway requires the existence of enzymes with prephenate dehydratase (PDT) activity (EC 4.2.1.51) in plants. Using phylogenetic studies, functional complementation assays in yeast and biochemical analysis, we have identified the enzymes displaying PDT activity in Pinus pinaster. Through sequence alignment comparisons and site-directed mutagenesis we have identified a 22-amino acid region conferring PDT activity (PAC domain) and a single Ala314 residue critical to trigger this activity. Our results demonstrate that all plant clades include PAC domain-containing ADTs, suggesting that the PDT activity, and thus the ability to synthesize Phe using phenylpyruvate as an intermediate, has been preserved throughout the evolution of plants. Moreover, this pathway together with the arogenate pathway gives plants a broad and versatile capacity to synthesize Phe and its derived compounds. PAC domain-containing enzymes are also present in green and red algae, and glaucophytes, the three emerging clades following the primary endosymbiont event resulting in the acquisition of plastids in eukaryotes. The evolutionary prokaryotic origin of this domain is discussed.
authors.affiliation: Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos, Málaga, 29071, Spain.
authors.forename: Jorge
authors.initials: J
authors.lastname: El-Azaz
authors.affiliation: Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos, Málaga, 29071, Spain.
authors.forename: Fernando
authors.initials: F
authors.lastname: de la Torre
authors.affiliation: Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos, Málaga, 29071, Spain.
authors.forename: Concepción
authors.initials: C
authors.lastname: Ávila
authors.affiliation: Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos, Málaga, 29071, Spain.
authors.forename: Francisco M
authors.initials: FM
authors.lastname: Cánovas
mesh_terms: D000600:Amino Acids, Dicarboxylic / Q000378:metabolism; D053138:Cyclohexenes / Q000378:metabolism; D017343:Genes, Plant / Q000502:physiology; D053858:Metabolic Networks and Pathways / Q000502:physiology; D010649:Phenylalanine / Q000378:metabolism; D010667:Phenylpyruvic Acids / Q000378:metabolism; D010802:Phylogeny; D028223:Pinus / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D010944:Plants; D011302:Prephenate Dehydratase / Q000235:genetics* / Q000378:metabolism; D014443:Tyrosine / Q000031:analogs & derivatives / Q000378:metabolism
chemical_list: D000600:Amino Acids, Dicarboxylic; D053138:Cyclohexenes; D010667:Phenylpyruvic Acids; D014443:Tyrosine; D010649:Phenylalanine; C015478:pretyrosine; D011302:Prephenate Dehydratase; C031606:phenylpyruvic acid
keywords: Pinus pinaster; Saccharomyces cerevisiae; chloroplast; phenylalanine; phenylpyruvate; prephenate dehydratase