Periplasmic phosphorylation of lipid A is linked to the synthesis of undecaprenyl phosphate.
One-third of the lipid A found in the Escherichia coli outer membrane contains an unsubstituted diphosphate unit at position 1 (lipid A 1-diphosphate). We now report an inner membrane enzyme, LpxT (YeiU), which specifically transfers a phosphate group to lipid A, forming the 1-diphosphate species. (32)P-labelled lipid A obtained from lpxT mutants do not produce lipid A 1-diphosphate. In vitro assays with Kdo(2)-[4'-(32)P]lipid A as the acceptor shows that LpxT uses undecaprenyl pyrophosphate as the substrate donor. Inhibition of lipid A 1-diphosphate formation in wild-type bacteria was demonstrated by sequestering undecaprenyl pyrophosphate with the cyclic polypeptide antibiotic bacitracin, providing evidence that undecaprenyl pyrophosphate serves as the donor substrate within whole bacteria. LpxT-catalysed phosphorylation is dependent upon transport of lipid A across the inner membrane by MsbA, a lipid A flippase, indicating a periplasmic active site. In conclusion, we demonstrate a novel pathway in the periplasmic modification of lipid A that is directly linked to the synthesis of undecaprenyl phosphate, an essential carrier lipid required for the synthesis of various bacterial polymers, such as peptidoglycan.
Touzé
Thierry
T
Laboratoire des Enveloppes Bactériennes et Antibiotiques, Unité Mixte de Recherche 8619 CNRS, Université Paris-Sud, 91405 Orsay, France.
Tran
An X
AX
Hankins
Jessica V
JV
Mengin-Lecreulx
Dominique
D
Trent
M Stephen
MS
D018528:ATP-Binding Cassette Transporters / Q000378:metabolism; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001414:Bacitracin / Q000494:pharmacology; D001426:Bacterial Proteins / Q000378:metabolism; D048168:Escherichia coli K12 / Q000201:enzymology / Q000235:genetics; D008050:Lipid A / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008563:Membrane Lipids / Q000378:metabolism; D009154:Mutation; D010458:Peptidyl Transferases / Q000378:metabolism; D019897:Periplasm / Q000201:enzymology*; D010710:Phosphates / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D011106:Polyisoprenyl Phosphates / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000378:metabolism; D011755:Pyrophosphatases / Q000235:genetics / Q000378:metabolism
D018528:ATP-Binding Cassette Transporters; D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D008050:Lipid A; D008563:Membrane Lipids; C079726:MsbA protein, Bacteria; D010710:Phosphates; D011106:Polyisoprenyl Phosphates; D001414:Bacitracin; C009621:undecaprenyl phosphate; D010458:Peptidyl Transferases; D011755:Pyrophosphatases; C503879:undecaprenyl pyrophosphate phosphatase