Biosynthesis of 1-deoxy-1-imino-D-erythrose 4-phosphate: a defining metabolite in the aminoshikimate pathway.
With respect to the source of the nitrogen atom incorporated into the aminoshikimate pathway, d-erythrose 4-phosphate has been proposed to undergo a transamination reaction resulting in formation of 1-deoxy-1-imino-d-erythrose 4-phosphate. Condensation of this metabolite with phosphoenolpyruvate catalyzed by aminoDAHP synthase would then hypothetically form the 4-amino-3,4-dideoxy-d-arabino-heptulosonic acid 7-phosphate (aminoDAHP), which is the first committed intermediate of the aminoshikimate pathway. However, in vitro formation of aminoDAHP has not been observed. In this account, the possibility is examined that 3-amino-3-deoxy-d-fructose 6-phosphate is the source of the nitrogen atom of the aminoshikimate pathway. Transketolase-catalyzed ketol transfer from 3-amino-3-deoxy-d-fructose 6-phosphate to d-ribose 5-phosphate would hypothetically release 1-deoxy-1-imino-d-erythrose 4-phosphate. Along these lines, a chemoenzymatic synthesis of 3-amino-3-deoxy-d-fructose 6-phosphate was elaborated. Incubation of 3-amino-3-deoxy-d-fructose 6-phosphate in Amycolatopsis mediterranei crude cell lysate with d-ribose 5-phosphate and phosphoenolpyruvate resulted in the formation of aminoDAHP and 3-amino-5-hydroxybenzoic acid. 3-[15N]-Amino-3-deoxy-d-6,6-[2H2]-fructose 6-phosphate was also synthesized and similarly incubated in A. mediterranei crude cell lysate. Retention of both 15N and 2H2 labeling in product aminoDAHP indicates that 3-amino-3-deoxy-d-fructose 6-phosphate is serving as a sequestered form of 1-deoxy-1-imino-d-erythrose 4-phosphate.
Guo
Jiantao
J
Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA.
Frost
J W
JW
D010723:3-Deoxy-7-Phosphoheptulonate Synthase / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D005636:Fructosephosphates / Q000378:metabolism; D050111:Imino Sugars; D012765:Shikimic Acid / Q000378:metabolism*; D013780:Tetroses / Q000096:biosynthesis*; D014174:Transketolase / Q000235:genetics / Q000378:metabolism
C450939:1-deoxy-1-imino-erythrose 4-phosphate; D005636:Fructosephosphates; D050111:Imino Sugars; D013780:Tetroses; D012765:Shikimic Acid; C027618:fructose-6-phosphate; D014174:Transketolase; D010723:3-Deoxy-7-Phosphoheptulonate Synthase