tailieunhanh - Báo cáo khoa học: Biosynthesis of isoprenoids – studies on the mechanism of 2C-methyl-D-erythritol-4-phosphate synthase

2C-Methyl-d-erythritol-4-phosphate synthase, encoded by the ispC gene (also designated dxr), catalyzes the first committed step in the nonmevalo-nate isoprenoid biosynthetic pathway. The reaction involves the isomeriza-tion of 1-deoxy-d-xylulose 5-phosphate, giving a branched-chain aldose derivative that is subsequently reduced to 2C-methyl-d-erythritol 4-phos-phate. | ễFEBS Journal Biosynthesis of isoprenoids - studies on the mechanism of 2C-methyl-D-erythritol-4-phosphate synthase Susan Lauw Victoria Illarionova Adelbert Bacher Felix Rohdich and Wolfgang Eisenreich Center for Integrated Protein Research Lehrstuhlfur Biochemie Department Chemie Technische Universitat Munchen Garching Germany Keywords deoxyxylulose dimethylallyl diphosphate isopentenyldiphosphate terpene Correspondence W. Eisenreich Center for Integrated Protein Research Lehrstuhl fur Biochemie Department Chemie Technische Universitat Munchen Lichtenbergstr. 4 D-85747 Garching Germany Fax 49 89 289 13363 Tel 49 89 289 13336 E-mail F. Rohdich Center for Integrated Protein Research Lehrstuhl fur Biochemie Department Chemie Technische Universitat Munchen Lichtenbergstr. 4 D-85747 Garching Germany Fax 49 89 289 13363 Tel 49 89 289 13336 E-mail Received 11 March 2008 revised 8 June 2008 accepted 11 June 2008 doi 2C-Methyl-D-erythritol-4-phosphate synthase encoded by the ispC gene also designated dxr catalyzes the first committed step in the nonmevalonate isoprenoid biosynthetic pathway. The reaction involves the isomerization of 1-deoxy-D-xylulose 5-phosphate giving a branched-chain aldose derivative that is subsequently reduced to 2C-methyl-D-erythritol 4-phos-phate. The isomerization step has been proposed to proceed as an intramolecular rearrangement or a retroaldol-aldol sequence. We report the preparation of 13C-labeled substrate isotopologs that were designed to optimize the detection of an exchange of putative cleavage products that might occur in the hypothetical retroaldol-aldol reaction sequence. In reaction mixtures containing large amounts of 2C-methyl-D-erythritol-4-phosphate synthase from Escherichia coli Mycobacterium tuberculosis or Arabidop-sis thaliana and a mixture of 1-13C1 -2C-methyl-D-erythritol 4-phosphate and 3-13C1 2C-methyl-D-erythritol 4-phosphate the .