Function 
UDP-N-acetylglucosamine acyltransferase or 
Acyl-[acyl-carrier-protein]--UDP-N-acetylglucosamine O-acyltransferase (LpxA) initiates lipid A biosynthesis.  It catalyzes the transfer of 3-hydroxymyristic acid from acyl carrier protein to the 3'-hydroxyl group of UDP-GlcNAc[1].
  Structural highlights 
The  of LpxA interacts with the substrate UDP moiety and the Glc-NAc moiety. It contains a  where the His acts as a general base and Asp helps to orient the His for participation in the catalysis[2].