RRC ID 31029
Author Dornfeld C, Weisberg AJ, K C R, Dudareva N, Jelesko JG, Maeda HA.
Title Phylobiochemical characterization of class-Ib aspartate/prephenate aminotransferases reveals evolution of the plant arogenate phenylalanine pathway.
Journal Plant Cell
Abstract The aromatic amino acid Phe is required for protein synthesis and serves as the precursor of abundant phenylpropanoid plant natural products. While Phe is synthesized from prephenate exclusively via a phenylpyruvate intermediate in model microbes, the alternative pathway via arogenate is predominant in plant Phe biosynthesis. However, the molecular and biochemical evolution of the plant arogenate pathway is currently unknown. Here, we conducted phylogenetically informed biochemical characterization of prephenate aminotransferases (PPA-ATs) that belong to class-Ib aspartate aminotransferases (AspAT Ibs) and catalyze the first committed step of the arogenate pathway in plants. Plant PPA-ATs and succeeding arogenate dehydratases (ADTs) were found to be most closely related to homologs from Chlorobi/Bacteroidetes bacteria. The Chlorobium tepidum PPA-AT and ADT homologs indeed efficiently converted prephenate and arogenate into arogenate and Phe, respectively. A subset of AspAT Ib enzymes exhibiting PPA-AT activity was further identified from both Plantae and prokaryotes and, together with site-directed mutagenesis, showed that Thr-84 and Lys-169 play key roles in specific recognition of dicarboxylic keto (prephenate) and amino (aspartate) acid substrates. The results suggest that, along with ADT, a gene encoding prephenate-specific PPA-AT was transferred from a Chlorobi/Bacteroidetes ancestor to a eukaryotic ancestor of Plantae, allowing efficient Phe and phenylpropanoid production via arogenate in plants today.
Volume 26(7)
Pages 3101-14
Published 2014-7-1
DOI 10.1105/tpc.114.127407
PII tpc.114.127407
PMID 25070637
PMC PMC4145135
MeSH Amino Acid Sequence Amino Acids, Dicarboxylic / metabolism Aspartate Aminotransferases / genetics* Aspartate Aminotransferases / metabolism Bacterial Proteins / genetics Bacterial Proteins / metabolism Biosynthetic Pathways Chlorobium / enzymology Chlorobium / genetics Conserved Sequence Cyclohexenes / metabolism Evolution, Molecular Hydro-Lyases / genetics Hydro-Lyases / metabolism Molecular Sequence Data Mutagenesis, Site-Directed Phenylalanine / metabolism* Phylogeny Plant Proteins / genetics Plant Proteins / metabolism Plants / enzymology* Plants / genetics Sequence Alignment Transaminases / genetics* Transaminases / metabolism Tyrosine / analogs & derivatives Tyrosine / metabolism
IF 9.618
Times Cited 17
DNA material Genomic DNA of Thermus thermophilus JCM 10941T (JGD05989).
General Microbes