Subsystem: Siderophore Enterobactin

This subsystem's description is:

Siderophore enterobactin is a triscatechol derivative of a cyclic triserine lactone that enables bacteria to recover iron from their environment. Believed earlier to be unique to Gram-negative bacteria, enterobactin has been isolated recently from two Gram-positive Streptomyces species. It is a cyclic compound of three 2,3-dihydroxybenzoylserine units joined in a cyclic structure by lactone linkages (see molecular diagram on slide two). Enterobactin is synthesized under low iron concentration conditions and excreted into the environment where it binds Fe(III) with high affinity and specificity. The ferrisiderophore complexes are taken up into the cell by specific ATP-binding cassette transporter complex.

From (Chen et al., 2009): Enterobactin biosynthesis proceeds via an upper chemical pathway that forms 2,3-dihydroxybenzoate (2,3-DHB) from chorismate and a lower, iterative pathway that assembles enterobactin from L-serine and 2,3-DHB. The lower pathway (see Tab “Illustrations”) employs the two nonribosomal peptide synthetases (NRPSs) EntB and EntF. The phosphopantetheinyl transferase (PPTase) “EntD” catalyzes the transfer of pantetheinephosphate from CoA to the Ser residue of the 2,3-DHB carrier domain of EntB and of the peptidyl carrier domain of EntF to generate holo-EntB and holo-EntF, respectively. EntE catalyzes the adenylation of 2,3-DHB and the subsequent aroyl transfer to the pantetheine thiol of holo-EntB. The adenylation domain of holo-EntF catalyzes the adenylation of L-Ser and subsequent transfer of an acyl group to the pantetheine thiol carrier domain of holo-EntF. The EntF condensation domain then catalyzes the transfer of the 2,3-DHB unit to the amine group of the EntF-tethered L-Ser. The 2,3-DHB-Ser unit is then transferred to the active site Ser of the EntF cyclizing thioesterase domain, thereby freeing the pantetheine thiol for acquisition of a second 2,3-DHB-Ser-DHB unit. It in turn is transferred to the Ser moiety side chain of 2,3-DHB-Ser tethered to the TE domain. Following the addition of a third 2,3-DHB-Ser unit, the chain is cyclized by the thioesterase domain to form enterobactin.

The genes encoding the enterobactin biosynthetic enzymes are clustered within cotranscriptional units, one of which includes EntC and EntA of the upper pathway and EntE, EntB, and EntH (also known as ybdB) of the lower pathway.

For more information, please check out the description and the additional notes tabs, below

Literature ReferencesEnterobactin: an archetype for microbial iron transport. Raymond KN Proceedings of the National Academy of Sciences of the United States of America 2003 Apr 112655062
Reconstitution and characterization of the Escherichia coli enterobactin synthetase from EntB, EntE, and EntF. Gehring AM Biochemistry 1998 Feb 249485415
Enterobactin synthase polypeptides of Escherichia coli are present in an osmotic-shock-sensitive cytoplasmic locality. Hantash FM Microbiology (Reading, England) 1997 Jan9025288
The EntF and EntE adenylation domains of Escherichia coli enterobactin synthetase: sequestration and selectivity in acyl-AMP transfers to thiolation domain cosubstrates. Ehmann DE Proceedings of the National Academy of Sciences of the United States of America 2000 Mar 1410688898
DiagramFunctional RolesSubsystem SpreadsheetDescriptionAdditional Notes 
Group Alias
Abbrev.Functional RoleReactionsScenario ReactionsGOLiterature
SubsetsColoring
collapsed
expanded


  
display  items per page
«first  «prevdisplaying 1 - 276 of 276next»  last»
Taxonomy Pattern 
Organism 
Domain
Variant [?] 
active
entCentB1entB2entAentEentDentFentHybdZEntSFesFepBFepCFepDFepGFepEFepARegPfeAPfeSPfeR
«first  «prevdisplaying 1 - 276 of 276next»  last»
Siderophore enterobactin is a triscatechol derivative of a cyclic triserine lactone that enables bacteria to recover iron from their environment. Believed earlier to be unique to Gram-negative bacteria, enterobactin has been isolated recently from two Gram-positive Streptomyces species. It is a cyclic compound of three 2,3-dihydroxybenzoylserine units joined in a cyclic structure by lactone linkages (see molecular diagram on slide two). Enterobactin is synthesized under low iron concentration conditions and excreted into the environment where it binds Fe(III) with high affinity and specificity. The ferrisiderophore complexes are taken up into the cell by specific ATP-binding cassette transporter complex.

From (Chen et al., 2009): Enterobactin biosynthesis proceeds via an upper chemical pathway that forms 2,3-dihydroxybenzoate (2,3-DHB) from chorismate and a lower, iterative pathway that assembles enterobactin from L-serine and 2,3-DHB. The lower pathway (see Tab “Illustrations”) employs the two nonribosomal peptide synthetases (NRPSs) EntB and EntF. The phosphopantetheinyl transferase (PPTase) “EntD” catalyzes the transfer of pantetheinephosphate from CoA to the Ser residue of the 2,3-DHB carrier domain of EntB and of the peptidyl carrier domain of EntF to generate holo-EntB and holo-EntF, respectively. EntE catalyzes the adenylation of 2,3-DHB and the subsequent aroyl transfer to the pantetheine thiol of holo-EntB. The adenylation domain of holo-EntF catalyzes the adenylation of L-Ser and subsequent transfer of an acyl group to the pantetheine thiol carrier domain of holo-EntF. The EntF condensation domain then catalyzes the transfer of the 2,3-DHB unit to the amine group of the EntF-tethered L-Ser. The 2,3-DHB-Ser unit is then transferred to the active site Ser of the EntF cyclizing thioesterase domain, thereby freeing the pantetheine thiol for acquisition of a second 2,3-DHB-Ser-DHB unit. It in turn is transferred to the Ser moiety side chain of 2,3-DHB-Ser tethered to the TE domain. Following the addition of a third 2,3-DHB-Ser unit, the chain is cyclized by the thioesterase domain to form enterobactin.

The genes encoding the enterobactin biosynthetic enzymes are clustered within cotranscriptional units, one of which includes EntC and EntA of the upper pathway and EntE, EntB, and EntH (also known as ybdB) of the lower pathway.
References:

1. Chen D, Wu R, Bryan TL, Dunaway-Mariano D. 2009. In vitro kinetic analysis of substrate specificity in enterobactin biosynthetic lower pathway enzymes provides insight into the biochemical function of the hot dog-fold thioesterase EntH. Biochemistry, 48(3):511-3.

2. Keseler I.M., Collado-Vides J., Gama-Castro S., Ingraham J., Paley S., Paulsen I.T., Peralta-Gil M., and Karp P.D. 2005. “EcoCyc: a comprehensive database resource for Escherichia coli” Nucleic Acids Research, Vol. 33, Database issue, D334-D337

3. K.N. Raymond, E.A. Dertz, and S.S. Kim. 2003. Enterobactin: An archetype for microbial iron transport. PNAS 100, 3584-3588

4. Hantash F.M., Ammerlaan M., and Earhart C.F. 1997. "Enterobactin synthase polypeptides of Escherichia coli are present in an osmotic-shock-sensitive cytoplasmic locality." Microbiology 143, 147-56.

5. Neidhardt FC, Curtiss III R, Ingraham JL, Lin ECC, Low Jr KB, Magasanik B, Reznikoff WS, Riley M, Schaechter M, Umbarger HE "Escherichia coli and Salmonella, Cellular and Molecular Biology, Second Edition." American Society for Microbiology, Washington, D.C., 1996