Reaction: (1) 4-amino-4-deoxy-α-L-arabinopyranosyl ditrans,octacis-undecaprenyl phosphate + α-Kdo-(2→4)-α-Kdo-(2→6)-lipid A = α-Kdo-(2→4)-Kdo-(2→6)-[4-P-L-Ara4N]-lipid A + ditrans,octacis-undecaprenyl phosphate
(2) 4-amino-4-deoxy-α-L-arabinopyranosyl ditrans,octacis-undecaprenyl phosphate + lipid IVA = lipid IIA + ditrans,octacis-undecaprenyl phosphate
(3) 4-amino-4-deoxy-α-L-arabinopyranosyl ditrans,octacis-undecaprenyl phosphate + α-Kdo-(2→4)-α-Kdo-(2→6)-lipid IVA = 4'-α-L-Ara4N-α-Kdo-(2→4)-α-Kdo-(2→6)-lipid IVA + ditrans,octacis-undecaprenyl phosphate
For diagram of reaction click here.
Glossary: lipid IVA = 2-deoxy-2-{[(3R)-3-hydroxytetradecanoyl]amino}-3-O-[(3R)-3-hydroxytetradecanoyl]-4-O-phospho-β-D-glucopyranosyl-(1→6)-2-deoxy-3-O-[(3R)-3-hydroxytetradecanoyl]-2-{[(3R)-3-hydroxytetradecanoyl]amino}-1-O-phospho-α-D-glucopyranose
lipid IIA = 4-amino-4-deoxy-β-L-arabinopyranosyl 2-deoxy-2-{[(3R)-3-hydroxytetradecanoyl]amino}-3-O-[(3R)-3-hydroxytetradecanoyl]-4-O-phospho-β-D-glucopyranosyl-(1→6)-2-deoxy-3-O-[(3R)-3-hydroxytetradecanoyl]-2-{[(3R)-3-hydroxytetradecanoyl]amino}-α-D-glucopyranosyl phosphate
α-Kdo-(2→4)-α-Kdo-(2→6)-lipid IVA = (3-deoxy-α-D-manno-oct-2-ulopyranosylonate)-(2→4)-(3-deoxy-α-D-manno-oct-2-ulopyranosylonate)-(2→6)-2-deoxy-2-{[(3R)-3-hydroxytetradecanoyl]amino}-3-O-[(3R)-3-hydroxytetradecanoyl]-4-O-phosphono-β-D-glucopyranosyl-(1→6)-2-deoxy-3-O-[(3R)-3-hydroxytetradecanoyl]-2-{[(3R)-3-hydroxytetradecanoyl]amino}-1-O-phosphono-α-D-glucopyranose
4'-α-L-Ara4N-α-Kdo-(2→4)-α-Kdo-(2→6)-lipid IVA = 4-amino-4-deoxy-α-L-arabinopyranosyl 2-deoxy-2-[(3R)-3-hydroxytetradecanamido]-3-O-[(3R)-3-hydroxytetradecanoyl]-4-phospho-β-D-glucopyranosy-(1→6)-2-deoxy-2-[(3R)-3-hydroxytetradecanamido]-3-O-[(3R)-3-hydroxytetradecanoyl]-α-D-glucopyranosyl phosphate
lipid A = lipid A of Escherichia coli = 2-deoxy-2-{[(3R)-3-(dodecanoyloxy)tetradecanoyl]amino}-3-O-[(3R)-3-(tetradecanoyloxy)tetradecanoyl]-4-O-phospho-β-D-glucopyranosyl-(1→6)-2-deoxy-3-O-[(3R)-3-hydroxytetradecanoyl]-2-{[(3R)-3-hydroxytetradecanoyl]amino}-1-O-phospho-α-D-glucopyranose
α-Kdo-(2→4)-α-Kdo-(2→6)-lipid A = (3-deoxy-α-D-manno-oct-2-ulopyranosylonate)-(2→4)-(3-deoxy-α-D-manno-oct-2-ulopyranosylonate)-(2→6)-2-deoxy-2-{[(3R)-3-(dodecanoyloxy)tetradecanoyl]amino}-3-O-[(3R)-3-(tetradecanoyloxy)tetradecanoyl]-4-O-phospho-β-D-glucopyranosyl-(1→6)-2-deoxy-3-O-[(3R)-3-hydroxytetradecanoyl]-2-{[(3R)-3-hydroxytetradecanoyl]amino}-1-O-phospho-α-D-glucopyranose
α-Kdo-(2→4)-α-Kdo-(2→6)-[4'-P-α-L-Ara4N]-lipid A = (3-deoxy-α-D-manno-oct-2-ulopyranosylonate)-(2→4)-(3-deoxy-α-D-manno-oct-2-ulopyranosylonate)-(2→6)-2-deoxy-2-{[(3R)-3-(dodecanoyloxy)tetradecanoyl]amino}-3-O-[(3R)-3-(tetradecanoyloxy)tetradecanoyl]-4-O-(4-amino-4-deoxy-α-L-arabinopyranosyl)phospho-β-D-glucopyranosyl-(1→6)-2-deoxy-3-O-[(3R)-3-hydroxytetradecanoyl]-2-{[(3R)-3-hydroxytetradecanoyl]amino}-1-O-phospho-α-D-glucopyranose
Other name(s): undecaprenyl phosphate-α-L-Ara4N transferase; 4-amino-4-deoxy-L-arabinose lipid A transferase; polymyxin resistance protein PmrK, arnT (gene name)
Systematic name: 4-amino-4-deoxy-α-L-arabinopyranosyl ditrans,octacis-undecaprenyl phosphate:lipid IVA 4-amino-4-deoxy-L-arabinopyranosyltransferase
Comments: 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: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number:
References:
1. Trent, M.S., Ribeiro, A.A., Lin, S., Cotter, R.J. and 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 (2001) 43122-43131. [PMID: 11535604]
2. Trent, M.S., Ribeiro, A.A., Doerrler, W.T., Lin, S., Cotter, R.J. and 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 (2001) 43132-43144. [PMID: 11535605]
3. Zhou, Z., Ribeiro, A.A., Lin, S., Cotter, R.J., Miller, S.I. and 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 (2001) 43111-43121. [PMID: 11535603]
4. Bretscher, L.E., Morrell, M.T., Funk, A.L. and Klug, C.S. Purification and characterization of the L-Ara4N transferase protein ArnT from Salmonella typhimurium. Protein Expr. Purif. 46 (2006) 33-39. [PMID: 16226890]
5. Impellitteri, N.A., Merten, J.A., Bretscher, L.E. and Klug, C.S. Identification of a functionally important loop in Salmonella typhimurium ArnT. Biochemistry 49 (2010) 29-35. [PMID: 19947657]