Enterobactin Biosynthesis in Escherichia coli: Isochorismate Lyase (EntB) Is a Bifunctional Enzyme That Is Phosphopantetheinylated by EntD and Then Acylated by EntE Using ATP and 2,3-Dihydroxybenzoate

Citations Over TimeTop 10% of 1997 papers

Abstract

In Escherichia coli, the siderophore molecule enterobactin is synthesized in response to iron deprivation by formation of an amide bond between 2,3-dihydroxybenzoate (2,3-DHB) and l-serine and formation of ester linkages between three such N-acylated serine residues. We show that EntB, previously described as the isochorismate lyase required for production of 2,3-DHB, is a bifunctional protein that also serves as an aryl carrier protein (ArCP) with a role in enterobactin assembly. EntB is phosphopantetheinylated near the C terminus in a reaction catalyzed by EntD with a kcat of 5 min-1 and a Km for apo-EntB of 6.5 microM. This holo-EntB is then acylated with 2,3-DHB in a reaction catalyzed by EntE, previously described as the 2,3-DHB-AMP ligase, with a kcat of 100 min-1 and a Km of <<1 microM for holo-EntB. The N-terminal 187 amino acids of EntB (isochorismate lyase domain) are not needed for reaction of EntB with either EntD or EntE as demonstrated by the equivalent catalytic efficiencies of the full-length EntB (residues 1-285) and the C-terminal EntB ArCP domain (residues 188-285) as substrates for both EntD and EntE.

Related Papers

• → Enterobactin Biosynthesis in Escherichia coli: Isochorismate Lyase (EntB) Is a Bifunctional Enzyme That Is Phosphopantetheinylated by EntD and Then Acylated by EntE Using ATP and 2,3-Dihydroxybenzoate(1997)218 cited
• → Characterization of a New Bifunctional and Cold-Adapted Polysaccharide Lyase (PL) Family 7 Alginate Lyase from Flavobacterium sp.(2020)29 cited
• → Catalytic Cycle of the Bifunctional Enzyme Phosphoribosyl-ATP Pyrophosphohydrolase/Phosphoribosyl-AMP Cyclohydrolase(2023)8 cited
• → l -Malyl-Coenzyme A Lyase/β-Methylmalyl-Coenzyme A Lyase from Chloroflexus aurantiacus , a Bifunctional Enzyme Involved in Autotrophic CO ₂ Fixation(2002)55 cited
• → Methenyltetrahydrofolate Cyclohydrolase Is Rate Limiting for the Enzymatic Conversion of 10-Formyltetrahydrofolate to 5,10-Methylenetetrahydrofolate in Bifunctional Dehydrogenase-Cyclohydrolase Enzymes(1998)35 cited