Details
| Original language | English |
|---|---|
| Pages (from-to) | 4476-91 |
| Number of pages | 16 |
| Journal | The plant cell |
| Volume | 23 |
| Issue number | 12 |
| Publication status | Published - Dec 2011 |
Abstract
5-Aminolevulinic acid (ALA) is the universal precursor for tetrapyrrole biosynthesis and is synthesized in plants in three enzymatic steps: ligation of glutamate (Glu) to tRNA(Glu) by glutamyl-tRNA synthetase, reduction of activated Glu to Glu-1-semialdehyde by glutamyl-tRNA reductase (GluTR), and transamination to ALA by Glu 1-semialdehyde aminotransferase. ALA formation controls the metabolic flow into the tetrapyrrole biosynthetic pathway. GluTR is proposed to be the key regulatory enzyme that is tightly controlled at transcriptional and posttranslational levels. We identified a GluTR binding protein (GluTRBP; previously called PROTON GRADIENT REGULATION7) that is localized in chloroplasts and part of a 300-kD protein complex in the thylakoid membrane. Although the protein does not modulate activity of ALA synthesis, the knockout of GluTRBP is lethal in Arabidopsis thaliana, whereas mutants expressing reduced levels of GluTRBP contain less heme. GluTRBP expression correlates with a function in heme biosynthesis. It is postulated that GluTRBP contributes to subcompartmentalized ALA biosynthesis by maintaining a portion of GluTR at the plastid membrane that funnels ALA into the heme biosynthetic pathway. These results regarding GluTRBP support a model of plant ALA synthesis that is organized in two separate ALA pools in the chloroplast to provide appropriate substrate amounts for balanced synthesis of heme and chlorophyll.
Keywords
- Agrobacterium tumefaciens/genetics, Aldehyde Oxidoreductases/genetics, Amino Acid Sequence, Aminolevulinic Acid/metabolism, Arabidopsis/genetics, Arabidopsis Proteins/genetics, Carrier Proteins/genetics, Chlorophyll/biosynthesis, Chloroplasts/metabolism, Escherichia coli/genetics, Gene Expression Regulation, Plant, Genes, Plant, Heme/genetics, Molecular Sequence Data, Plants, Genetically Modified/genetics, Plasmids/genetics, Protein Interaction Mapping, RNA Interference, RNA, Plant/genetics, Recombinant Proteins/genetics, Thylakoid Membrane Proteins/genetics, Tobacco/genetics, Transcription, Genetic, Two-Hybrid System Techniques
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In: The plant cell, Vol. 23, No. 12, 12.2011, p. 4476-91.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - An Arabidopsis GluTR binding protein mediates spatial separation of 5-aminolevulinic acid synthesis in chloroplasts
AU - Czarnecki, Olaf
AU - Hedtke, Boris
AU - Melzer, Michael
AU - Rothbart, Maxi
AU - Richter, Andreas
AU - Schröter, Yvonne
AU - Pfannschmidt, Thomas
AU - Grimm, Bernhard
PY - 2011/12
Y1 - 2011/12
N2 - 5-Aminolevulinic acid (ALA) is the universal precursor for tetrapyrrole biosynthesis and is synthesized in plants in three enzymatic steps: ligation of glutamate (Glu) to tRNA(Glu) by glutamyl-tRNA synthetase, reduction of activated Glu to Glu-1-semialdehyde by glutamyl-tRNA reductase (GluTR), and transamination to ALA by Glu 1-semialdehyde aminotransferase. ALA formation controls the metabolic flow into the tetrapyrrole biosynthetic pathway. GluTR is proposed to be the key regulatory enzyme that is tightly controlled at transcriptional and posttranslational levels. We identified a GluTR binding protein (GluTRBP; previously called PROTON GRADIENT REGULATION7) that is localized in chloroplasts and part of a 300-kD protein complex in the thylakoid membrane. Although the protein does not modulate activity of ALA synthesis, the knockout of GluTRBP is lethal in Arabidopsis thaliana, whereas mutants expressing reduced levels of GluTRBP contain less heme. GluTRBP expression correlates with a function in heme biosynthesis. It is postulated that GluTRBP contributes to subcompartmentalized ALA biosynthesis by maintaining a portion of GluTR at the plastid membrane that funnels ALA into the heme biosynthetic pathway. These results regarding GluTRBP support a model of plant ALA synthesis that is organized in two separate ALA pools in the chloroplast to provide appropriate substrate amounts for balanced synthesis of heme and chlorophyll.
AB - 5-Aminolevulinic acid (ALA) is the universal precursor for tetrapyrrole biosynthesis and is synthesized in plants in three enzymatic steps: ligation of glutamate (Glu) to tRNA(Glu) by glutamyl-tRNA synthetase, reduction of activated Glu to Glu-1-semialdehyde by glutamyl-tRNA reductase (GluTR), and transamination to ALA by Glu 1-semialdehyde aminotransferase. ALA formation controls the metabolic flow into the tetrapyrrole biosynthetic pathway. GluTR is proposed to be the key regulatory enzyme that is tightly controlled at transcriptional and posttranslational levels. We identified a GluTR binding protein (GluTRBP; previously called PROTON GRADIENT REGULATION7) that is localized in chloroplasts and part of a 300-kD protein complex in the thylakoid membrane. Although the protein does not modulate activity of ALA synthesis, the knockout of GluTRBP is lethal in Arabidopsis thaliana, whereas mutants expressing reduced levels of GluTRBP contain less heme. GluTRBP expression correlates with a function in heme biosynthesis. It is postulated that GluTRBP contributes to subcompartmentalized ALA biosynthesis by maintaining a portion of GluTR at the plastid membrane that funnels ALA into the heme biosynthetic pathway. These results regarding GluTRBP support a model of plant ALA synthesis that is organized in two separate ALA pools in the chloroplast to provide appropriate substrate amounts for balanced synthesis of heme and chlorophyll.
KW - Agrobacterium tumefaciens/genetics
KW - Aldehyde Oxidoreductases/genetics
KW - Amino Acid Sequence
KW - Aminolevulinic Acid/metabolism
KW - Arabidopsis/genetics
KW - Arabidopsis Proteins/genetics
KW - Carrier Proteins/genetics
KW - Chlorophyll/biosynthesis
KW - Chloroplasts/metabolism
KW - Escherichia coli/genetics
KW - Gene Expression Regulation, Plant
KW - Genes, Plant
KW - Heme/genetics
KW - Molecular Sequence Data
KW - Plants, Genetically Modified/genetics
KW - Plasmids/genetics
KW - Protein Interaction Mapping
KW - RNA Interference
KW - RNA, Plant/genetics
KW - Recombinant Proteins/genetics
KW - Thylakoid Membrane Proteins/genetics
KW - Tobacco/genetics
KW - Transcription, Genetic
KW - Two-Hybrid System Techniques
U2 - 10.1105/tpc.111.086421
DO - 10.1105/tpc.111.086421
M3 - Article
C2 - 22180625
VL - 23
SP - 4476
EP - 4491
JO - The plant cell
JF - The plant cell
SN - 1040-4651
IS - 12
ER -