Isoprenoid Biosynthesis in Synechocystis sp. Strain PCC6803 Is Stimulated by Compounds of the Pentose Phosphate Cycle but Not by Pyruvate or Deoxyxylulose-5-Phosphate
AUTOR(ES)
Ershov, Yuri V.
FONTE
American Society for Microbiology
RESUMO
The photosynthetic cyanobacterium Synechocystis sp. strain PCC6803 possesses homologs of known genes of the non-mevalonate 2-C-methyl-d-erythritol 2-phosphate (MEP) pathway for synthesis of isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP). Isoprenoid biosynthesis in extracts of this cyanobacterium, measured by incorporation of radiolabeled IPP, was not stimulated by pyruvate, an initial substrate of the MEP pathway in Escherichia coli, or by deoxyxylulose-5-phosphate, the first pathway intermediate in E. coli. However, high rates of IPP incorporation were obtained with addition of dihydroxyacetone phosphate (DHAP) and glyceraldehyde 3-phosphate (GA3P), as well as a variety of pentose phosphate cycle compounds. Fosmidomycin (at 1 μM and 1 mM), an inhibitor of deoxyxylulose-5-phosphate reductoisomerase, did not significantly inhibit phototrophic growth of the cyanobacterium, nor did it affect [14C]IPP incorporation stimulated by DHAP plus GA3P. To date, it has not been possible to unequivocally demonstrate IPP isomerase activity in this cyanobacterium. The combined results suggest that the MEP pathway, as described for E. coli, is not the primary path by which isoprenoids are synthesized under photosynthetic conditions in Synechocystis sp. strain PCC6803. Our data support alternative routes of entry of pentose phosphate cycle substrates derived from photosynthesis.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=135332Documentos Relacionados
- Inactivation of sll1556 in Synechocystis Strain PCC 6803 Impairs Isoprenoid Biosynthesis from Pentose Phosphate Cycle Substrates In Vitro
- The desA gene of the cyanobacterium Synechocystis sp. strain PCC6803 is the structural gene for delta 12 desaturase.
- Accumulation of Inorganic Polyphosphate in phoU Mutants of Escherichia coli and Synechocystis sp. Strain PCC6803
- Characterization of the norB Gene, Encoding Nitric Oxide Reductase, in the Nondenitrifying Cyanobacterium Synechocystis sp. Strain PCC6803
- The role of an alternative sigma factor in motility and pilus formation in the cyanobacterium Synechocystis sp. strain PCC6803