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Folate synthesis in plants: the last step of the p-aminobenzoate branch is catalyzed by a plastidial aminodeoxychorismate lyase.
Plant J. 2004 Nov; 40(4):453-61.PJ

Abstract

In plants, the last step in the synthesis of p-aminobenzoate (PABA) moiety of folate remains to be elucidated. In Escherichia coli, this step is catalyzed by the PabC protein, a beta-lyase that converts 4-amino-4-deoxychorismate (ADC)--the reaction product of the PabA and PabB enzymes--to PABA and pyruvate. So far, the only known plant enzyme involved in PABA synthesis is ADC synthase, which has fused domains homologous to E. coli PabA and PabB and is located in plastids. ADC synthase has no lyase activity, implying that plants have a separate ADC lyase. No such lyase is known in any eukaryote. Genomic and phylogenetic approaches identified Arabidopsis and tomato cDNAs encoding PabC homologs with putative chloroplast-targeting peptides. These cDNAs were shown to encode functional enzymes by complementation of an E. coli pabC mutant, and by demonstrating that the partially purified recombinant proteins convert ADC to PABA. Plant ADC lyase is active as dimer and is not feedback inhibited by physiologic concentrations of PABA, its glucose ester, or folates. The full-length Arabidopsis ADC lyase polypeptide was translocated into isolated pea chloroplasts and, when fused to green fluorescent protein, directed the passenger protein to Arabidopsis chloroplasts in transient expression experiments. These data indicate that ADC lyase, like ADC synthase, is present in plastids. As shown previously for the ADC synthase transcript, the level of ADC lyase mRNA in the pericarp of tomato fruit falls sharply as ripening advances, suggesting that the expression of these two enzymes is coregulated.

Authors+Show Affiliations

Horticultural Sciences Department, University of Florida, Gainesville, FL 32611, USA.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, Non-P.H.S.

Language

eng

PubMed ID

15500462

Citation

Basset, Gilles J C., et al. "Folate Synthesis in Plants: the Last Step of the P-aminobenzoate Branch Is Catalyzed By a Plastidial Aminodeoxychorismate Lyase." The Plant Journal : for Cell and Molecular Biology, vol. 40, no. 4, 2004, pp. 453-61.
Basset GJ, Ravanel S, Quinlivan EP, et al. Folate synthesis in plants: the last step of the p-aminobenzoate branch is catalyzed by a plastidial aminodeoxychorismate lyase. Plant J. 2004;40(4):453-61.
Basset, G. J., Ravanel, S., Quinlivan, E. P., White, R., Giovannoni, J. J., Rébeillé, F., Nichols, B. P., Shinozaki, K., Seki, M., Gregory, J. F., & Hanson, A. D. (2004). Folate synthesis in plants: the last step of the p-aminobenzoate branch is catalyzed by a plastidial aminodeoxychorismate lyase. The Plant Journal : for Cell and Molecular Biology, 40(4), 453-61.
Basset GJ, et al. Folate Synthesis in Plants: the Last Step of the P-aminobenzoate Branch Is Catalyzed By a Plastidial Aminodeoxychorismate Lyase. Plant J. 2004;40(4):453-61. PubMed PMID: 15500462.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Folate synthesis in plants: the last step of the p-aminobenzoate branch is catalyzed by a plastidial aminodeoxychorismate lyase. AU - Basset,Gilles J C, AU - Ravanel,Stéphane, AU - Quinlivan,Eoin P, AU - White,Ruth, AU - Giovannoni,James J, AU - Rébeillé,Fabrice, AU - Nichols,Brian P, AU - Shinozaki,Kazuo, AU - Seki,Motoaki, AU - Gregory,Jesse F,3rd AU - Hanson,Andrew D, PY - 2004/10/27/pubmed PY - 2005/2/3/medline PY - 2004/10/27/entrez SP - 453 EP - 61 JF - The Plant journal : for cell and molecular biology JO - Plant J VL - 40 IS - 4 N2 - In plants, the last step in the synthesis of p-aminobenzoate (PABA) moiety of folate remains to be elucidated. In Escherichia coli, this step is catalyzed by the PabC protein, a beta-lyase that converts 4-amino-4-deoxychorismate (ADC)--the reaction product of the PabA and PabB enzymes--to PABA and pyruvate. So far, the only known plant enzyme involved in PABA synthesis is ADC synthase, which has fused domains homologous to E. coli PabA and PabB and is located in plastids. ADC synthase has no lyase activity, implying that plants have a separate ADC lyase. No such lyase is known in any eukaryote. Genomic and phylogenetic approaches identified Arabidopsis and tomato cDNAs encoding PabC homologs with putative chloroplast-targeting peptides. These cDNAs were shown to encode functional enzymes by complementation of an E. coli pabC mutant, and by demonstrating that the partially purified recombinant proteins convert ADC to PABA. Plant ADC lyase is active as dimer and is not feedback inhibited by physiologic concentrations of PABA, its glucose ester, or folates. The full-length Arabidopsis ADC lyase polypeptide was translocated into isolated pea chloroplasts and, when fused to green fluorescent protein, directed the passenger protein to Arabidopsis chloroplasts in transient expression experiments. These data indicate that ADC lyase, like ADC synthase, is present in plastids. As shown previously for the ADC synthase transcript, the level of ADC lyase mRNA in the pericarp of tomato fruit falls sharply as ripening advances, suggesting that the expression of these two enzymes is coregulated. SN - 0960-7412 UR - https://www.unboundmedicine.com/medline/citation/15500462/Folate_synthesis_in_plants:_the_last_step_of_the_p_aminobenzoate_branch_is_catalyzed_by_a_plastidial_aminodeoxychorismate_lyase_ L2 - https://onlinelibrary.wiley.com/resolve/openurl?genre=article&sid=nlm:pubmed&issn=0960-7412&date=2004&volume=40&issue=4&spage=453 DB - PRIME DP - Unbound Medicine ER -