EC - N2-citryl-N6-acetyl-N6-hydroxylysine synthase

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IntEnz Enzyme Nomenclature


Accepted name:
N2-citryl-N6-acetyl-N6-hydroxylysine synthase
Other names:
Nα-citryl-Nε-acetyl-Nε-hydroxylysine synthase
iucA (gene name)
Systematic name:
citrate:N6-acetyl-N6-hydroxy-L-lysine ligase (AMP-forming)




Requires Mg2+. The enzyme is involved in the biosynthesis of aerobactin, a dihydroxamate siderophore. It belongs to a class of siderophore synthases known as type A nonribosomal peptide synthase-independent synthases (NIS). Type A enzymes are responsible for the formation of amide or ester bonds between polyamines or amino alcohols and a prochiral carboxyl group of citrate. The enzyme is believed to form an adenylate intermediate prior to ligation. Formerly EC

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB


  1. Appanna, D.L., Grundy, B.J., Szczepan, E.W. and Viswanatha, T.
    Aerobactin synthesis in a cell-free system of Aerobacter aerogenes 62-1.
    Biochim. Biophys. Acta 801 : 437-443 (1984).
  2. Gibson, F., Magrath, D. I.
    The isolation and characterization of a hydroxamic acid (aerobactin) formed by Aerobacter aerogenes 62-I.
    Biochim. Biophys. Acta 192 : 175-184 (1969). [PMID: 4313071]
  3. Maurer, P.J. and Miller, M.
    Microbial iron chelators: total synthesis of aerobactin and its constituent amino acid, N6-acetyl-N6-hydroxylysine.
    J. Am. Chem. Soc. 104 : 3096-3101 (1982).
  4. de Lorenzo, V., Bindereif, A., Paw, B. H., Neilands, J. B.
    Aerobactin biosynthesis and transport genes of plasmid ColV-K30 in Escherichia coli K-12.
    J. Bacteriol. 165 : 570-578 (1986). [PMID: 2935523]
  5. Challis, G. L.
    A widely distributed bacterial pathway for siderophore biosynthesis independent of nonribosomal peptide synthetases.
    Chembiochem 6 : 601-611 (2005). [PMID: 15719346]
  6. Oves-Costales, D., Kadi, N., Challis, G. L.
    The long-overlooked enzymology of a nonribosomal peptide synthetase-independent pathway for virulence-conferring siderophore biosynthesis.
    Chem. Commun. (Camb.) 6530-6541 (2009). [PMID: 19865642]

[EC created 2012, modified 2019]