Subsystem: Histidine Biosynthesis in plants

This subsystem's description is:

Histidine in plants is formed by the same pathway as in prokaryotes, through a series of 11 reactions beginning with the condensation of ATP and phosphoribosylpyrophosphate (PRPP)
Plant enzymes in histidine biosynthesis pathway are also targets for herbicide discovery since this metabolic pathway is not present in animals. Recent physiological studies have indicated novel functions for histidine in plants as chelators and transporters of metal ions, and interesting connections of histidine with plant reproduction (Stepansky, Leustek, 2006)

References
Stepansky A, Leustek T. 2006. Histidine biosynthesis in plants. Amino Acids,30(2):127-42. PMID: 16547652

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This subsystem incorporates the following AraCyc pathway:
histidine biosynthesis: HISTSYN-PWY
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This subsystem encodes protein families associated with this pathway. They are listed under the “Functional Roles” Tab (green banner above). Note that the complement of genes implementing each Functional Role in plant genomes can differ in PlantSEED from those given in AraCyc. To ensure the accuracy and consistency of plant genome annotation (i) only genes with experimental or strong bioinformatics support are assigned specific Functional Roles, and (ii) uniform annotations are used for orthologous genes, consistent across all plant genomes and also with their orthologs in Eubacteria and Archaea (where applicable) throughout the SEED database. Enzymatic steps believed to be present in plants, but not yet associated with any sequences, are flagged “missing_gene”

The “Spreadsheet” Tab contains a Table where each row represents a plant genome, each column corresponds to a Functional Role, and each cell is populated with the gene(s)/protein(s) that implement this Functional Role in each organism. Each gene/protein is identified with a blue number – the Protein-Encoding Gene (PEG) ID - which is linked to an underlying detailed PEG page. Publications supporting functional assignments are posted there.

For more information, please check out the description and the additional notes tabs, below

DiagramFunctional RolesSubsystem SpreadsheetDescriptionAdditional Notes 

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Group Alias
Abbrev.Functional RoleReactionsScenario ReactionsGOLiterature
SubsetsColoring
collapsed
expanded


  
Taxonomy Pattern 
Organism 
Domain
Variant [?] 
active
HISN1HISN2aHISN2bHISN3HISN4aHISN4bHISN5HISN6*EC_HisBHISN8PurA
Histidine in plants is formed by the same pathway as in prokaryotes, through a series of 11 reactions beginning with the condensation of ATP and phosphoribosylpyrophosphate (PRPP)
Plant enzymes in histidine biosynthesis pathway are also targets for herbicide discovery since this metabolic pathway is not present in animals. Recent physiological studies have indicated novel functions for histidine in plants as chelators and transporters of metal ions, and interesting connections of histidine with plant reproduction (Stepansky, Leustek, 2006)

References
Stepansky A, Leustek T. 2006. Histidine biosynthesis in plants. Amino Acids,30(2):127-42. PMID: 16547652

==============================
This subsystem incorporates the following AraCyc pathway:
histidine biosynthesis: HISTSYN-PWY
==============================
This subsystem encodes protein families associated with this pathway. They are listed under the “Functional Roles” Tab (green banner above). Note that the complement of genes implementing each Functional Role in plant genomes can differ in PlantSEED from those given in AraCyc. To ensure the accuracy and consistency of plant genome annotation (i) only genes with experimental or strong bioinformatics support are assigned specific Functional Roles, and (ii) uniform annotations are used for orthologous genes, consistent across all plant genomes and also with their orthologs in Eubacteria and Archaea (where applicable) throughout the SEED database. Enzymatic steps believed to be present in plants, but not yet associated with any sequences, are flagged “missing_gene”

The “Spreadsheet” Tab contains a Table where each row represents a plant genome, each column corresponds to a Functional Role, and each cell is populated with the gene(s)/protein(s) that implement this Functional Role in each organism. Each gene/protein is identified with a blue number – the Protein-Encoding Gene (PEG) ID - which is linked to an underlying detailed PEG page. Publications supporting functional assignments are posted there.
Overview of Histidine biosynthesis in prokaryotes:
PRPP, from the pentose phosphate pathway, and ATP are the substrates of the first reaction catalyzed by ATP phosphoribosyltransferase (HisA). This is a highly regulated phosphotransferase. HisAa, is an ATP phosphoribosyltransferase catalytic subunit, and HisAb and HisAb2 are ATP phosphoribosyltransferase regulatory subunits that may assist in the formation of the first product of the pathway, phosphoribosyl-ATP. The next three steps in the pathway include phosphoribosyl-ATP pyrophosphatase, phosphoribosyl-AMP cyclohydrolase and phosphoribosylformimino-5-aminoimidazole carboxamide ribotide isomerase (HisB, HisC, and HisD, respectively). Imidazole glycerol phosphate synthase has a cyclase subunit (HisEa) and an amidotransferase subunit (His Eb). These steps are followed by ones catalyzed by imidazoleglycerol-phosphate dehydratase (HisF), and histidinol-phosphate aminotransferase (HisG). Histidinol-phosphatase (HisH), the next step in the pathway, may have an alternative form (HisH2). The final step of the histidine pathway, histidinol dehydrogenase (HisI) produces L-Histidine.