|
PLANT PHYSIOLOGY , Vol 111, Issue 2 507-514, Copyright © 1996 by American Society of Plant Biologists
|
BIOCHEMISTRY AND ENZYMOLOGY |
Anthranilate Synthase from Ruta graveolens (Duplicated AS[alpha] Genes Encode Tryptophan-Sensitive and Tryptophan-Insensitive Isoenzymes Specific to Amino Acid and Alkaloid Biosynthesis)
J. Bohlmann, T. Lins, W. Martin and U. Eilert
Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340 (J.B.)
Anthranilate synthase (AS, EC 4.1.3.27) catalyzes the conversion of
chorismate into anthranilate, the biosynthetic precursor of both tryptophan
and numerous secondary metabolites, including inducible plant defense
compounds. The higher plant Ruta graveolens produces tryptophan and
elicitor-inducible, anthranilate-derived alkaloids by means of two
differentially expressed nuclear genes for chloroplast-localized AS[alpha]
subunits, AS[alpha]1 and AS[alpha]2. Mechanisms that partition chorismate
between tryptophan and inducible alkaloids thus do not entail
chloroplast/cytosol separation of AS isoenzymes and yet might involve
differential feedback regulation of pathway-specific AS[alpha] subunits.
The two AS[alpha] isoenzymes of R. graveolens were expressed as glutathione
S-transferase fusion proteins in Escherichia coli deletion mutants
defective in AS activity and were purified to homogeneity. Differential
sensitivity of the transformed E. coli strains toward 5-methyltryptophan, a
false-feedback inhibitor of AS, was demonstrated. Characterization of
affinity-purified AS[alpha] isoenzymes revealed that the noninducible
AS[alpha]2 of R. graveolens is strongly feedback inhibited by 10 [mu]M
tryptophan. In contrast, the elicitor-inducible AS[alpha]1 isoenzyme is
only slightly affected even by tryptophan concentrations 10-fold higher
than those observed in planta. These results are consistent with the
hypothesis that chorismate flux into biosynthesis of tryptophan and
defense-related alkaloid biosynthesis in R. graveolens is regulated at the
site of AS[alpha] isoenzymes at both genetic and enzymatic levels.
This article has been cited by other articles:

|
 |

|
 |
 
P. Barone, X.-H. Zhang, and J. M. Widholm
Tobacco plastid transformation using the feedback-insensitive anthranilate synthase [{alpha}]-subunit of tobacco (ASA2) as a new selectable marker
J. Exp. Bot.,
July 1, 2009;
60(11):
3195 - 3202.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
T. Kanno, A. Komatsu, K. Kasai, J. G. Dubouzet, M. Sakurai, Y. Ikejiri-Kanno, K. Wakasa, and Y. Tozawa
Structure-Based in Vitro Engineering of the Anthranilate Synthase, a Metabolic Key Enzyme in the Plant Tryptophan Pathway
Plant Physiology,
August 1, 2005;
138(4):
2260 - 2268.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
R. A. Caldo, D. Nettleton, and R. P. Wise
Interaction-Dependent Gene Expression in Mla-Specified Response to Barley Powdery Mildew
PLANT CELL,
September 1, 2004;
16(9):
2514 - 2528.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
Y. Tozawa, H. Hasegawa, T. Terakawa, and K. Wakasa
Characterization of Rice Anthranilate Synthase {alpha}-Subunit Genes OASA1 and OASA2. Tryptophan Accumulation in Transgenic Rice Expressing a Feedback-Insensitive Mutant of OASA1
Plant Physiology,
August 1, 2001;
126(4):
1493 - 1506.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
M. Zook
Biosynthesis of Camalexin from Tryptophan Pathway Intermediates in Cell-Suspension Cultures of Arabidopsis
Plant Physiology,
December 1, 1998;
118(4):
1389 - 1393.
[Abstract]
[Full Text]
|
 |
|

|
 |

|
 |
 
H.-S. Song, J. E. Brotherton, R. A. Gonzales, and J. M. Widholm
Tissue Culture-Specific Expression of a Naturally Occurring Tobacco Feedback-Insensitive Anthranilate Synthase
Plant Physiology,
June 1, 1998;
117(2):
533 - 543.
[Abstract]
[Full Text]
|
 |
|

|
 |

|
 |
 
D. Melanson, M.-D. Chilton, D. Masters-Moore, and W. S. Chilton
A deletion in an indole synthase gene is responsible for the DIMBOA-deficient phenotype of bxbx maize
PNAS,
November 25, 1997;
94(24):
13345 - 13350.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
J. Bohlmann, C. L. Steele, and R. Croteau
Monoterpene Synthases from Grand Fir (Abies grandis). cDNA ISOLATION, CHARACTERIZATION, AND FUNCTIONAL EXPRESSION OF MYRCENE SYNTHASE, (-)-(4S)-LIMONENE SYNTHASE, AND (-)-(1S,5S)-PINENE SYNTHASE
J. Biol. Chem.,
August 29, 1997;
272(35):
21784 - 21792.
[Abstract]
[Full Text]
[PDF]
|
 |
|
|
|