IUBMB Enzyme Nomenclature


Accepted name: UDP-3-O-(3-hydroxyacyl)glucosamine N-acyltransferase

Reaction: a (3R)-3-hydroxyacyl-[acyl-carrier protein] + a UDP-3-O-[(3R)-3-hydroxyacyl]-α-D-glucosamine = a UDP-2-N,3-O-bis[(3R)-3-hydroxyacyl]-α-D-glucosamine + a holo-[acyl-carrier protein]

For diagram of reaction click here

Other name(s): lpxD (gene name); UDP-3-O-acyl-glucosamine N-acyltransferase; UDP-3-O-(R-3-hydroxymyristoyl)-glucosamine N-acyltransferase; acyltransferase LpxD; acyl-ACP:UDP-3-O-(3-hydroxyacyl)-GlcN N-acyltransferase; firA (gene name); (3R)-3-hydroxymyristoyl-[acyl-carrier protein]:UDP-3-O-[(3R)-3-hydroxymyristoyl]-α-D-glucosamine N-acetyltransferase; UDP-3-O-(3-hydroxymyristoyl)glucosamine N-acyltransferase; (3R)-3-hydroxytetradecanoyl-[acyl-carrier protein]:UDP-3-O-[(3R)-3-hydroxytetradecanoyl]-α-D-glucosamine N-acetyltransferase

Systematic name: (3R)-3-hydroxyacyl-[acyl-carrier protein]:UDP-3-O-[(3R)-3-hydroxyacyl]-α-D-glucosamine N-acyltransferase

Comments: The enzyme catalyses a step of lipid A biosynthesis. LpxD from Escherichia coli prefers (3R)-3-hydroxytetradecanoyl-[acyl-carrier protein] [3], but it does not have an absolute specificity for 14-carbon hydroxy fatty acids, as it can transfer other fatty acids, including odd-chain fatty acids, if they are available to the organism [5].

Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number:


1. Kelly, T.M., Stachula, S.A., Raetz, C.R. and Anderson, M.S. The firA gene of Escherichia coli encodes UDP-3-O-(R-3-hydroxymyristoyl)-glucosamine N-acyltransferase. The third step of endotoxin biosynthesis. J. Biol. Chem. 268 (1993) 19866-19874. [PMID: 8366125]

2. Buetow, L., Smith, T.K., Dawson, A., Fyffe, S. and Hunter, W.N. Structure and reactivity of LpxD, the N-acyltransferase of lipid A biosynthesis. Proc. Natl. Acad. Sci. USA 104 (2007) 4321-4326. [PMID: 17360522]

3. Bartling, C.M. and Raetz, C.R. Steady-state kinetics and mechanism of LpxD, the N-acyltransferase of lipid A biosynthesis. Biochemistry 47 (2008) 5290-5302. [PMID: 18422345]

4. Bainbridge, B.W., Karimi-Naser, L., Reife, R., Blethen, F., Ernst, R.K. and Darveau, R.P. Acyl chain specificity of the acyltransferases LpxA and LpxD and substrate availability contribute to lipid A fatty acid heterogeneity in Porphyromonas gingivalis. J. Bacteriol. 190 (2008) 4549-4558. [PMID: 18456814]

5. Bartling, C.M. and Raetz, C.R. Crystal structure and acyl chain selectivity of Escherichia coli LpxD, the N-acyltransferase of lipid A biosynthesis. Biochemistry 48 (2009) 8672-8683. [PMID: 19655786]

6. Badger, J., Chie-Leon, B., Logan, C., Sridhar, V., Sankaran, B., Zwart, P.H. and Nienaber, V. Structure determination of LpxD from the lipopolysaccharide-synthesis pathway of Acinetobacter baumannii. Acta Crystallogr. Sect. F Struct. Biol. Cryst. Commun. 69 (2013) 6-9. [PMID: 23295477]

7. Kroeck, K.G., Sacco, M.D., Smith, E.W., Zhang, X., Shoun, D., Akhtar, A., Darch, S.E., Cohen, F., Andrews, L.D., Knox, J.E. and Chen, Y. Discovery of dual-activity small-molecule ligands of Pseudomonas aeruginosa LpxA and LpxD using SPR and X-ray crystallography. Sci. Rep. 9 (2019) 15450. [PMID: 31664082]

[EC created 2010, modified 2021]

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