EC - Lipid IVA 4-amino-4-deoxy-L-arabinosyltransferase

  IntEnz view ENZYME view

IntEnz Enzyme Nomenclature


Accepted name:
lipid IVA 4-amino-4-deoxy-L-arabinosyltransferase
Other names:
lipid A 4-amino-4-deoxy-L-arabinosyltransferase
undecaprenyl phosphate-α-L-Ara4N transferase
4-amino-4-deoxy-L-arabinose lipid A transferase
polymyxin resistance protein PmrK
undecaprenyl phosphate-α-4-amino-4-deoxy-L-arabinose arabinosyl transferase
Systematic name:
4-amino-4-deoxy-α-L-arabinopyranosyl ditrans,octacis-undecaprenyl phosphate:lipid IVA di-trans,octa-cis-undecaprenyl phosphate:lipid IVA L-2-aminoarabinopyranosyltransferasetransferase



Integral membrane protein present in the inner membrane of certain Gram negative endobacteria. In strains that do not produce 3-deoxy-D-manno-octulosonic acid (Kdo), the enzyme adds a single arabinose unit to the 1-phosphate moiety of the tetra-acylated lipid A precursor, lipid IVA. In the presence of a Kdo disaccharide, the enzyme primarily adds an arabinose unit to the 4-phosphate of lipid A molecules. The Salmonella typhimurium enzyme can add arabinose units to both positions.

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB
Gene Ontology: GO:0103015
UniProtKB/Swiss-Prot: (79) [show] [UniProt]


  1. Trent, M. S., Ribeiro, A. A., Lin, S., Cotter, R. J., Raetz, C. R.
    An inner membrane enzyme in Salmonella and Escherichia coli that transfers 4-amino-4-deoxy-L-arabinose to lipid A: induction on polymyxin-resistant mutants and role of a novel lipid-linked donor.
    J. Biol. Chem. 276: 43122-43131 (2001). [PMID: 11535604]
  2. Trent, M. S., Ribeiro, A. A., Doerrler, W. T., Lin, S., Cotter, R. J., Raetz, C. R.
    Accumulation of a polyisoprene-linked amino sugar in polymyxin-resistant Salmonella typhimurium and Escherichia coli: structural characterization and transfer to lipid A in the periplasm.
    J. Biol. Chem. 276: 43132-43144 (2001). [PMID: 11535605]
  3. Zhou, Z., Ribeiro, A. A., Lin, S., Cotter, R. J., Miller, S. I., Raetz, C. R.
    Lipid A modifications in polymyxin-resistant Salmonella typhimurium: PMRA-dependent 4-amino-4-deoxy-L-arabinose, and phosphoethanolamine incorporation.
    J. Biol. Chem. 276: 43111-43121 (2001). [PMID: 11535603]
  4. Bretscher, L. E., Morrell, M. T., Funk, A. L., Klug, C. S.
    Purification and characterization of the L-Ara4N transferase protein ArnT from Salmonella typhimurium.
    Protein Expr. Purif. 46: 33-39 (2006). [PMID: 16226890]
  5. Impellitteri, N. A., Merten, J. A., Bretscher, L. E., Klug, C. S.
    Identification of a functionally important loop in Salmonella typhimurium ArnT.
    Biochemistry 49: 29-35 (2010). [PMID: 19947657]

[EC created in 2010, modified 2011]