Redox regulation of Arabidopsis 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase.
The cDNA for 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase of Arabidopsis encodes a polypeptide with an amino-terminal signal sequence for plastid import. A cDNA fragment encoding the processed form of the enzyme was expressed in Escherichia coli. The resulting protein was purified to electrophoretic homogeneity. The enzyme requires Mn(2+) and reduced thioredoxin (TRX) for activity. Spinach (Spinacia oleracea) TRX f has an apparent dissociation constant for the enzyme of about 0.2 microM. The corresponding constant for TRX m is orders of magnitude higher. In the absence of TRX, dithiothreitol partially activates the enzyme. Upon alkylation of the enzyme with iodoacetamide, the dependence on a reducing agent is lost. These results indicate that the first enzyme in the shikimate pathway of Arabidopsis appears to be regulated by the ferredoxin/TRX redox control of the chloroplast.
Entus
Robert
R
Department of Biochemistry, Purdue University, West Lafayette, Indiana 47907, USA.
Poling
Michael
M
Herrmann
Klaus M
KM
D010723:3-Deoxy-7-Phosphoheptulonate Synthase / Q000187:drug effects / Q000302:isolation & purification / Q000378:metabolism*; D000478:Alkylation; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D008345:Manganese / Q000737:chemistry / Q000494:pharmacology; D010084:Oxidation-Reduction; D012765:Shikimic Acid / Q000378:metabolism; D013879:Thioredoxins / Q000494:pharmacology
D012765:Shikimic Acid; D008345:Manganese; D013879:Thioredoxins; D010723:3-Deoxy-7-Phosphoheptulonate Synthase