Deblocking the common pathway of aromatic amino acid synthesis

A tyrR- E. coli cell transformed with exogenous DNA sequences comprising gene sequences encoding common aromatic amino acid pathway enzymes wherein the DNA sequences encoding the common aromatic amino acid pathway enzymes consist of genes encoding the enzyme species 3-dehydroquinate synthase, 5-enolpyruvoyl-shikimate-3-phosphate synthase and chorismate synthase.

An E. coli cell characterized by the enhanced expression of a selected group of genes of the common aromatic amino acid pathway enzymes, said selected group of genes consisting of genes encoding the enzymes 3-dehydroquinate synthase, shikimate kinase, 5-enolpyruvoyl-shikimate-3-phosphate synthase, chorismate synthase, transketolase, and 3-deoxy-D-arabino-heptulosonate-7-phosphate synthase.

A DNA construct comprising a selected group of structural genes encoding common aromatic amino acid pathway enzyme species, wherein the sequences of said construct encoding the common aromatic amino acid pathway enzymes consist of gene sequences encoding 3-dehydroquinate synthase, shikimate kinase, 5-enolpyruvoyl-shikimate-3-phosphate synthase and chorismate synthase.

A method of using a DNA construct for enhancing the production of compounds synthesized by the common aromatic amino acid biosynthesis pathway, in an E. coli host cell, said method comprising the steps of

• introducing said DNA construct into the E. coli host cell, said DNA construct comprising genes encoding for common aromatic amino acid pathway enzymes, wherein the DNA sequences encoding the common aromatic amino acid pathway enzymes consist of genes encoding the enzymes 3-dehydroquinate synthase, shikimate kinase, 5-enolpyruvoyl-shikimate-3-phosphate synthase, and chorismate synthase;
• and culturing the cell transformant in media containing an assimilable carbon source under conditions conducive to the assimilation of said carbon source and wherein production of compounds synthesized by the common aromatic amino acid biosynthesis pathway is enhanced.

A plasmid construct selected from the group consisting of pKAD50 and pAB18B.

An E. coli strain selected from the group consisting of E. coli strain D2704/pKAD136/pKAD50, and E. coli strain KAD29B/pKD130A/pKAD77A.