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Nonflowering Plants Possess a Unique Folate-Dependent Phenylalanine Hydroxylase That Is Localized in Chloroplasts
- Source :
- Plant Cell, Plant Cell, American Society of Plant Biologists, 2010, 22 (10), pp.3410-22. ⟨10.1105/tpc.110.078824⟩, The Plant cell, The Plant cell, American Society of Plant Biologists (ASPB), 2010, 22 (10), pp.3410-22. ⟨10.1105/tpc.110.078824⟩, The Plant cell, 2010, 22 (10), pp.3410-22. ⟨10.1105/tpc.110.078824⟩
- Publication Year :
- 2010
- Publisher :
- Oxford University Press (OUP), 2010.
-
Abstract
- Tetrahydropterin-dependent aromatic amino acid hydroxylases (AAHs) are known from animals and microbes but not plants. A survey of genomes and ESTs revealed AAH-like sequences in gymnosperms, mosses, and algae. Analysis of full-length AAH cDNAs from Pinus taeda, Physcomitrella patens, and Chlamydomonas reinhardtii indicated that the encoded proteins form a distinct clade within the AAH family. These proteins were shown to have Phe hydroxylase activity by functional complementation of an Escherichia coli Tyr auxotroph and by enzyme assays. The P. taeda and P. patens AAHs were specific for Phe, required iron, showed Michaelian kinetics, and were active as monomers. Uniquely, they preferred 10-formyltetrahydrofolate to any physiological tetrahydropterin as cofactor and, consistent with preferring a folate cofactor, retained activity in complementation tests with tetrahydropterin-depleted E. coli host strains. Targeting assays in Arabidopsis thaliana mesophyll protoplasts using green fluorescent protein fusions, and import assays with purified Pisum sativum chloroplasts, indicated chloroplastic localization. Targeting assays further indicated that pterin-4a-carbinolamine dehydratase, which regenerates the AAH cofactor, is also chloroplastic. Ablating the single AAH gene in P. patens caused accumulation of Phe and caffeic acid esters. These data show that nonflowering plants have functional plastidial AAHs, establish an unprecedented electron donor role for a folate, and uncover a novel link between folate and aromatic metabolism.
- Subjects :
- 0106 biological sciences
Chloroplasts
Physcomitrella
Chlamydomonas reinhardtii
plant
Plant Science
phylogeny
MESH: Bryopsida
01 natural sciences
MESH: Recombinant Proteins
chemistry.chemical_compound
subcellular localization
Aromatic amino acids
Plant Proteins
MESH: Genetic Complementation Test
0303 health sciences
MESH: Plant Proteins
biology
MESH: Hydro-Lyases
food and beverages
bioinformatics
Recombinant Proteins
Chloroplast
Complementation
tetrahydropterin
Biochemistry
homogentisate pathway
MESH: Computational Biology
Phenylalanine hydroxylase
Molecular Sequence Data
MESH: Pterins
phenylalanine hydroxylase
phenylpropanoid
folate
Physcomitrella patens
MESH: Folic Acid
In Brief
moss
03 medical and health sciences
Folic Acid
chloroplast
evolution
[SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology
Hydro-Lyases
030304 developmental biology
MESH: Chloroplasts
MESH: Molecular Sequence Data
Genetic Complementation Test
Computational Biology
cofactor
Cell Biology
aromatic aminoacid hydroxylase
Pinus
biology.organism_classification
Bryopsida
Pterins
enzyme
chemistry
kinetics
Dehydratase
biology.protein
metabolism
010606 plant biology & botany
Subjects
Details
- ISSN :
- 1532298X and 10404651
- Volume :
- 22
- Database :
- OpenAIRE
- Journal :
- The Plant Cell
- Accession number :
- edsair.doi.dedup.....c0fda5bc5fbfc85ca2534b2ae21ffc24