EC Number   |
Substrates |
Organism |
Products  |
Reversibility |
|---|
    2.3.1.191 | more |
both LpxA and LpxD, from Escherichia coli are also able to incorporate odd-chain fatty acids into lipid A when grown in the presence of 1% propionic acid. When grown on 1% propionic acid lipid A also contains the odd-chain fatty acids tridecanoic acid (C13), pentadecanoic acid (C15), hydroxy tridecanoic acid (C13OH), and hydroxy pentadecanoic acid (C15OH). Escherichia coli lipid A acyltransferases do not have an absolute specificity for 14-carbon hydroxy fatty acids but can transfer fatty acids differing by one carbon unit if the fatty acid substrates are available |
Escherichia coli |
? |
- |
? |
| 2.3.1.191 | more |
His247 and His284 contribute to a mechanism involving nucleophilic attack by the amine of one substrate on the carbonyl carbon of an acyl carrier protein thioester conjugate |
Chlamydia trachomatis |
? |
- |
? |
| 2.3.1.191 | more |
lipid A from strains expressing either of the Porphyromonas gingivalis transferases contains 16-carbon hydroxy fatty acids in addition to the normal Escherichia coli 14-carbon hydroxy fatty acids, demonstrating that these acyltransferases display a relaxed acyl chain length specificity. Both LpxA and LpxD, from either Escherichia coli or Porphyromonas gingivalis are also able to incorporate odd-chain fatty acids into lipid A when grown in the presence of 1% propionic acid. The relaxed specificity of the Porphyromonas gingivalis lipid A acyltransferases and the substrate availability account for the lipid A structural clusters that differ by 14 mass units observed in Porphyromonas gingivalis lipopolysaccharide preparations |
Porphyromonas gingivalis |
? |
- |
? |
| 2.3.1.191 | more |
R-3-hydroxylauroyl-methylphosphopantetheine is a very poor substrate. The specific activity, measured at either 0.01 mM or 1 mM (3R)-3-hydroxylauroylmethylphosphopantetheine as the acyl donor, is more than 100fold lower than with 0.01 mM (3R)-3-hydroxymyristoyl-[acyl-carrier protein] |
Escherichia coli |
? |
- |
? |
| 2.3.1.191 | more |
fluorescent enzyme assay, method optimization, overview |
Escherichia coli |
? |
- |
? |
| 2.3.1.191 | more |
ordered-sequential reaction mechanism. Acyl-ACP binds first to free LpxD forming a binary complex. ACP associates with the ACP-recognition domain and the acyl-4'-phosphopantetheine group packs into the hydrophobic N-channel. UDP-acyl-GlcN binds next, which initiates acyl transfer. In the ternary product complex, the 4'-phosphopantetheine arm of hydrolysed-acyl-ACP completely encloses the reaction chamber, blocking UDP-diacyl-GlcN from leaving. By moving the 4'-phosphopantetheine group towards Met 290, the catalytic chamber opens up. This motion drives the eventual release of UDP-diacyl-GlcN and triggers conformational changes downstream of helix-II leading to holo-ACP dissociation |
Escherichia coli |
? |
- |
? |
| 2.3.1.191 | (3R)-3-hydroxymyristoyl-[acyl-carrier protein] + UDP-3-O-((3R)-3-hydroxymyristoyl)-alpha-D-glucosamine |
a comparison of the lipid A structures shows that in Escherichia coli and Neisseria meningitidis, LpxD can be expected to have the same specificity, both adding 3-hydroxymyristoyl chains |
Neisseria meningitidis |
UDP-2,3-bis((3R)-3-hydroxymyristoyl)-alpha-D-glucosamine + holo-[acyl-carrier protein] |
- |
? |
| 2.3.1.191 | (3R)-3-hydroxymyristoyl-[acyl-carrier protein] + UDP-3-O-((3R)-3-hydroxymyristoyl)-alpha-D-glucosamine |
since only (R)-3-hydroxymyristate is found at the 2,3,2, and 3 positions of Escherichia coli lipid A, it is reassuring that both Escherichia coli acyltransferases display extraordinary specificity for (R)-3-hydroxymyristoyl-[acyl-carrier protein] |
Escherichia coli |
UDP-2,3-bis((3R)-3-hydroxymyristoyl)-alpha-D-glucosamine + holo-[acyl-carrier protein] |
- |
? |
| 2.3.1.191 | (3R)-3-hydroxymyristoyl-[acyl-carrier protein] + UDP-3-O-((3R)-3-hydroxymyristoyl)-alpha-D-glucosamine |
myristoyl-[acyl-carrier protein] does not serve as an acyl donor for the overproduced UDP-3-O-((R)-3-hydroxymyristoyl)-GlcN N-acyltransferase |
Escherichia coli |
UDP-2,3-bis((3R)-3-hydroxymyristoyl)-alpha-D-glucosamine + holo-[acyl-carrier protein] |
- |
? |
| 2.3.1.191 | (R,S)-3-hydroxymyristoyl-[acyl-carrier protein] + UDP-3-O-((3R)-3-hydroxymyristoyl)-alpha-D-glucosamine |
wild-type LpxD prefers (R,S)-3-hydroxymyristoyl-[acyl-carrier protein] over (R,S)-3-hydroxypalmitoyl-[acyl-carrier protein] by a factor of 3, whereas the M290A mutant has the opposite selectivity |
Escherichia coli |
UDP-2,3-bis((3R)-3-hydroxymyristoyl)-alpha-D-glucosamine + holo-[acyl-carrier protein] |
- |
? |
