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

Lipid IVA 4-amino-4-deoxy-L-arabinosyltransferase
Ec Number:	2.4.2.43

Lipid IVA 4-amino-4-deoxy-L-arabinosyltransferase (undecaprenyl phosphate-alpha-L-Ara4N transferase, 4-amino-4-deoxy-L-arabinose lipid A transferase, polymyxin resistance protein PmrK, arnT (gene)) is an enzyme with systematic name 4-amino-4-deoxy-alpha-L-arabinopyranosyl ditrans, octacis-undecaprenyl phosphate:lipid IVA 4-amino-4-deoxy-L-arabinopyranosyltransferase.^{[1] [2] [3] [4] [5]} This enzyme catalyses the following chemical reaction

(1) 4-amino-4-deoxy-alpha-L-arabinopyranosyl ditrans, octacis-undecaprenyl phosphate + alpha-Kdo-(2->4)-alpha-Kdo-(2->6)-lipid A

\rightleftharpoons alpha-Kdo-(2->4)-alpha-Kdo-(2->6)-[4-P-L-Ara4N]-lipid A + ditrans, octacis-undecaprenyl phosphate

(2) 4-amino-4-deoxy-alpha-L-arabinopyranosyl ditrans, octacis-undecaprenyl phosphate + lipid IVA

\rightleftharpoons lipid IIA + ditrans, octacis-undecaprenyl phosphate

(3) 4-amino-4-deoxy-alpha-L-arabinopyranosyl ditrans, octacis-undecaprenyl phosphate + alpha-Kdo-(2->4)-alpha-Kdo-(2->6)-lipid IVA

\rightleftharpoons 4'-alpha-L-Ara4N-alpha-Kdo-(2->4)-alpha-Kdo-(2->6)-lipid IVA + ditrans, octacis-undecaprenyl phosphate

This integral membrane protein is present in the inner membrane of certain Gram negative endobacteria.

Notes and References

1. Trent MS, Ribeiro AA, Lin S, Cotter RJ, Raetz CR . 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 . The Journal of Biological Chemistry . 276 . 46 . 43122–31 . November 2001 . 11535604 . 10.1074/jbc.m106961200 . free .
2. Trent MS, Ribeiro AA, Doerrler WT, Lin S, Cotter RJ, Raetz CR . 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 . The Journal of Biological Chemistry . 276 . 46 . 43132–44 . November 2001 . 11535605 . 10.1074/jbc.m106962200 . free .
3. Zhou Z, Ribeiro AA, Lin S, Cotter RJ, Miller SI, Raetz CR . Lipid A modifications in polymyxin-resistant Salmonella typhimurium: PMRA-dependent 4-amino-4-deoxy-L-arabinose, and phosphoethanolamine incorporation . The Journal of Biological Chemistry . 276 . 46 . 43111–21 . November 2001 . 11535603 . 10.1074/jbc.m106960200 . free .
4. Bretscher LE, Morrell MT, Funk AL, Klug CS . Purification and characterization of the L-Ara4N transferase protein ArnT from Salmonella typhimurium . Protein Expression and Purification . 46 . 1 . 33–9 . March 2006 . 16226890 . 10.1016/j.pep.2005.08.028 .
5. Impellitteri NA, Merten JA, Bretscher LE, Klug CS . Identification of a functionally important loop in Salmonella typhimurium ArnT . Biochemistry . 49 . 1 . 29–35 . January 2010 . 19947657 . 2805049 . 10.1021/bi901572f .