Fig. 1

Genes used for β-carotene synthesis in engineered E. coli strains, vector constructs and the two artificial MVA operons. a Genes involved in β-carotene Production via both MEP and MVA pathways. The abbreviations for enzymes and pathway intermediates are as follows: atoB, gene of acetoacetyl-CoA thiolase; mvaS, gene of HMG-CoA synthase; Hmg1, truncated HMG-CoA reductase; erg12, gene of mevalonate kinase; mvaA, gene of HMG-CoA reductase; mvaD1, gene of mevalonate pyrophosphate decarboxylase; idi, gene of IPP isomerase; ispA, FPP synthase; crtEYIB, β-carotene synthesis operon from Pantoea agglomerans; b Plasmid maps of vectors with heterologous MVA genes; c Integrated artificial MVA pathway operons in E. coli chromosome at pflB and frdB sites