Function 
UDP-3-O-(3-hydroxymyristoyl)glucosamine N-acyltransferase or UDP-3-O-acylglucosamine N-acyltransferase
(LpxD) is involved in the third step of the biosynthesis of lipid A which is a phosphorylated glycolipid that anchors the lipopolysaccharide to the outer membrane of the cell.  Thus, LpxD is essential to survival of Gram-negative bacteria.  It catalyzes the N-acylation of UDP-3-O-(3-hydroxytetradeanoyl)glucosamine[1]. LpxD is structurally similar to LpxA which functions as the first enzye in the lipid A biosynthesis.
  Relevance 
LpxD inhibitors are antimicrobials[2].
  Structural highlights 
The biological assembly of UDP-3-O-(3-hydroxymyristoyl)glucosamine N-acyltransferase is  (PDB code 6uec). The 3D structure of LpxD complex with a ligand shows the binding site to be situated at . There are extensive polar interactions with LpxD as well as hydrogen bonds[3].