Figure 1From: Evolutionary diversification and characterization of the eubacterial gene family encoding DXR type II, an alternative isoprenoid biosynthetic enzymeIsoprenoid and amino acid biosynthetic pathways. A) Pathways for the biosynthesis of isoprenoid precursors. On the left, MVA pathway is represented. Enzymes are indicated in bold: AACT, acetoacetyl-CoA thiolase; HMGS, HMG-CoA synthase; HMGR, HMG-CoA reductase; MVK, mevalonate kinase; PMVK, 5-phosphomevalonate kinase; DPMD, 5-diphosphomevalonate decarboxylase; IDI, IPP/DMAPP isomerase. On the right, MEP pathway steps are described: GAP, D-glyceraldehyde 3-phosphate; DXP, 1-deoxy-D-xylulose 5-phosphate; MEP, 2-C-methyl-D-erythritol 4-phosphate; CDP-ME,4-diphosphocytidyl-2-C-methyl-D-erythritol; MEcPP, 2-C-methyl-D-erythritol 2,4-cyclodiphosphate; HMBPP, 4-hydroxy-3-methylbut-2-enyl diphosphate; IPP, isopentenyl diphosphate; DMAPP, dimethylallyl diphosphate. Enzymes are indicated in bold: DXS, DXP synthase; DXR, DXP reductoisomerase; MCT, MEP cytidylyltransferase; CMK, CDPME kinase; MDS, ME-cPP synthase; HDS, HMBPP synthase; HDR, HMBPP reductase; IDI, IPP isomerase. B) Amino acid biosynthesis. The common pathway (CP) is highlighted in black and enzymes indicated in bold: AK, aspartokinase; ASDH, aspartate semialdehyde dehydrogenase; HD, homoserine dehydrogenase. Solid arrows indicate single catalytic steps and dashed arrows mark multiple steps.Back to article page