Forms part of the defence mechanism against insects and microbial pathogens in the grass family, Gramineae, where it catalyses the first committed step in the formation of the cyclic hydroxamic acids 2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one (DIBOA) and 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one (DIMBOA) . This enzyme resembles the alpha-subunit of EC 4.2.1.20, tryptophan synthase , for which, (1S,2R)-1-C-(indol-3-yl)glycerol 3-phosphate is also a substrate, but, unlike tryptophan synthase, its activity is independent of the beta-subunit and free indole is released .
the indole is further converted to 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one, a secondary plant metabolite. BX1 cleaves indole-3-glycerol phosphate significantly faster to indole and glyceraldehyde 3-phosphate than the homologous alpha-subunit of tryptophan synthase, EC 4.2.1.20. In the primary metabolism, indole diffuses through the connecting tunnel to the beta-active site where it is condensed with serine to form tryptophan and water
Forms part of the defence mechanism against insects and microbial pathogens in the grass family, Gramineae, where it catalyses the first committed step in the formation of the cyclic hydroxamic acids 2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one (DIBOA) and 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one (DIMBOA) [1]. This enzyme resembles the alpha-subunit of EC 4.2.1.20, tryptophan synthase [3], for which, (1S,2R)-1-C-(indol-3-yl)glycerol 3-phosphate is also a substrate, but, unlike tryptophan synthase, its activity is independent of the beta-subunit and free indole is released [2].
indole release activated by beet armyworm and methyl salicylate is preceded by igl gene (encoding indole-3-glycerol phosphate lyase) induction within 1.5 h of treatment and declines within 6 h, induction of the IGL gene expression is not observed with (Z)-3-hexenol treatment
the indole is further converted to 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one, a secondary plant metabolite. BX1 cleaves indole-3-glycerol phosphate significantly faster to indole and glyceraldehyde 3-phosphate than the homologous alpha-subunit of tryptophan synthase, EC 4.2.1.20
the indole-3-glycerol phosphate lyase Igl is the structural gene of volatile indole biosynthesis in the tritrophic interaction in maize. The gene is activated on transcriptional level with the same kinetics and to the same level by the fatty acid amino acid conjugates volicitin and N-linolenoyl-L-glutamine. Both conjugates are present in the regurgitates of herbivorous caterpillars. Modifications of the fatty acid moiety of the fatty acid amino acid conjugates greatly reduces the elicitation of Igl and only the L-stereoisomer of the fatty acid amino acid conjugates shows biological activity in the system. Volicitin treatment leads to a fast increase of allene oxide synthase and allene oxide cyclase transcription levels and methyl jasmonate application induces Igl transcription. Hence,the induction of jasmonate biosynthesis appears to be an integral part of the elicitor mediated increase of Igl gene transcription
the indole is further converted to 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one, a secondary plant metabolite. BX1 cleaves indole-3-glycerol phosphate significantly faster to indole and glyceraldehyde 3-phosphate than the homologous alpha-subunit of tryptophan synthase, EC 4.2.1.20
indole release activated by beet armyworm and methyl salicylate is preceded by igl gene (encoding indole-3-glycerol phosphate lyase) induction within 1.5 h of treatment and declines within 6 h, induction of the IGL gene expression is not observed with (Z)-3-hexenol treatment
the indole-3-glycerol phosphate lyase Igl is the structural gene of volatile indole biosynthesis in the tritrophic interaction in maize. The gene is activated on transcriptional level with the same kinetics and to the same level by the fatty acid amino acid conjugates volicitin and N-linolenoyl-L-glutamine. Both conjugates are present in the regurgitates of herbivorous caterpillars. Modifications of the fatty acid moiety of the fatty acid amino acid conjugates greatly reduces the elicitation of Igl and only the L-stereoisomer of the fatty acid amino acid conjugates shows biological activity in the system. Volicitin treatment leads to a fast increase of allene oxide synthase and allene oxide cyclase transcription levels and methyl jasmonate application induces Igl transcription. Hence,the induction of jasmonate biosynthesis appears to be an integral part of the elicitor mediated increase of Igl gene transcription
in an isoform Igl deficient background, mutant plants deficient in chloroplastic isoform Bx1 allow better development of the cereal aphid Rhopalosiphum padi, and are affected in penetration resistance against the fungus Setosphaeria turtica. At stages preceding major tissue disruption, Rhopalosiphum padi and Setosphaeria turtica elicited increased accumulation of 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one-glucoside, 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one, and 2-hydroxy-4,7-dimethoxy-1,4-benzoxazin-3-one-glucoside (HDMBOA-glc), which is most pronounced in apoplastic leaf extracts. Chloroplastic isoform-deficient bx1 mutant lines deposite less chitosan-induced callose than Bx1 wild-type lines, whereas apoplast infiltration with 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one, but not HDMBOA-glc, mimicks chitosan-induced callose
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CRYSTALLIZATION (Commentary)
ORGANISM
UNIPROT
LITERATURE
the crystal structure of BX1 suggusts that the faster catalytic rate of BX1 compared to the homologous alpha-subuni8t of tryptophan synthase EC 4.2.1.20, may due to a stabilzation of the active conformation, loop alphaL6 is closed and the catalytic glutamate, Glu134 is in the active conformation. There are two crystallographically independent molecules in the asymmetric unit of the rhombohedral BX1 crystal form
Kulik, V.; Hartmann, E.; Weyand, M.; Frey, M.; Gierl, A.; Niks, D.; Dunn, M.F.; Schlichting, I.
On the structural basis of the catalytic mechanism and the regulation of the alpha subunit of tryptophan synthase from Salmonella typhimurium and BX1 from maize, two evolutionarily related enzymes
Transcriptional activation of Igl, the gene for indole formation in Zea mays: a structure-activity study with elicitor-active N-acyl glutamines from insects