2QIV: Structural Basis For The Acyl Chain Selectivity And Mechanism Of Udp- N-acetylglucosamine Acyltransferase

UDP-N-acetylglucosamine (UDP-GlcNAc) acyltransferase (LpxA) catalyzes the first step of lipid A biosynthesis, the reversible transfer of the R-3-hydroxyacyl chain from R-3-hydroxyacyl acyl carrier protein to the glucosamine 3-OH group of UDP-GlcNAc. Escherichia coli LpxA is highly selective for R-3-hydroxymyristate. The crystal structure of the E. coli LpxA homotrimer, determined previously in the absence of lipid substrates or products, revealed that LpxA contains an unusual, left-handed parallel beta-helix fold. We have now solved the crystal structures of E. coli LpxA with the bound product UDP-3-O-(R-3-hydroxymyristoyl)-GlcNAc at a resolution of 1.74 A and with bound UDP-3-O-(R-3-hydroxydecanoyl)-GlcNAc at 1.85 A. The structures of these complexes are consistent with the catalytic mechanism deduced by mutagenesis and with a recent 3.0-A structure of LpxA with bound UDP-GlcNAc. Our structures show how LpxA selects for 14-carbon R-3-hydroxyacyl chains and reveal two modes of UDP binding.
PDB ID: 2QIVDownload
MMDB ID: 59476
PDB Deposition Date: 2007/7/5
Updated in MMDB: 2017/10
Experimental Method:
x-ray diffraction
Resolution: 1.85  Å
Source Organism:
Similar Structures:
Biological Unit for 2QIV: trimeric; determined by author and by software (PISA)
Molecular Components in 2QIV
Label Count Molecule
Proteins (3 molecules)
Udp-n-acetylglucosamine Acyltransferase(Gene symbol: lpxA)
Molecule annotation
Chemicals (3 molecules)
* Click molecule labels to explore molecular sequence information.

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