Membrane spanning protein in TonB-ExbB-ExbD complex; Involved in the TonB-dependent energy-dependent transport of various receptor-bound substrates. Protects ExbD from proteolytic degradation and functionally stabilizes TonB.

Membrane spanning protein in TonB-ExbB-ExbD transport complex; Interacts with outer membrane receptor proteins that carry out high-affinity binding and energy dependent uptake into the periplasmic space of specific substrates such as cobalamin, and various iron compounds (such as iron dicitrate, enterochelin, aerobactin, etc.). In the absence of TonB these receptors bind their substrates but do not carry out active transport. TonB also interacts with some colicins and is involved in the energy-dependent, irreversible steps of bacteriophages phi 80 and T1 infection. It could act to tran [...]

Membrane spanning protein in TonB-ExbB-ExbD complex; Involved in the TonB-dependent energy-dependent transport of various receptor-bound substrates.

Ferrienterobactin outer membrane transporter; This protein is involved in the initial step of iron uptake by binding ferrienterobactin (Fe-ENT), an iron chelatin siderophore that allows E.coli to extract iron from the environment. FepA also acts as a receptor for colicins B and D.

Enterobactin synthase multienzyme complex component, ATP-dependent; Activates the carboxylate group of L-serine via ATP-dependent PPi exchange reactions to the aminoacyladenylate, preparing that molecule for the final stages of enterobactin synthesis. Holo-EntF acts as the catalyst for the formation of the three amide and three ester bonds present in the cyclic (2,3-dihydroxybenzoyl)serine trimer enterobactin, using seryladenylate and acyl-holo-EntB (acylated with 2,3-dihydroxybenzoate by EntE).

Colicin IA outer membrane receptor and translocator; Not yet known. Postulated to participate in iron transport. Outer membrane receptor for colicins IA and IB.

2,3-dihydro-2,3-dihydroxybenzoate dehydrogenase; Involved in the biosynthesis of the siderophore enterobactin (enterochelin), which is a macrocyclic trimeric lactone of N-(2,3- dihydroxybenzoyl)-serine. Catalyzes the reversible NAD-dependent oxidation of the C3-hydroxyl group of 2,3-dihydro-2,3-dihydroxybenzoate (2,3-diDHB), producing the transient intermediate 2-hydroxy-3-oxo-4,6- cyclohexadiene-1-carboxylate, which undergoes rapid aromatization to the final product, 2,3-dihydroxybenzoate (2,3-DHB). Only the compounds with a C3-hydroxyl group such as methyl 2,3-dihydro-2,3- dihydroxyb [...]

Isochorismate synthase 1; Involved in the biosynthesis of the siderophore enterobactin (macrocyclic trimeric lactone of N-(2,3-dihydroxybenzoyl)-serine). Catalyzes the reversible conversion of chorismate to isochorismate.

Isochorismatase; Involved in the biosynthesis of the siderophore enterobactin (enterochelin), which is a macrocyclic trimeric lactone of N-(2,3- dihydroxybenzoyl)-serine. The serine trilactone serves as a scaffolding for the three catechol functionalities that provide hexadentate coordination for the tightly ligated iron(2+) atoms. EntB is a bifunctional protein that serves as an isochorismate lyase and an aryl carrier protein (ArCP). Catalyzes the conversion of isochorismate to 2,3-dihydro-2,3-dihydroxybenzoate (2,3-diDHB), the precursor of 2,3- dihydroxybenzoate (DHB). In the enterob [...]