Catalyzes the N-acylation of UDP-3-O-(hydroxytetradecanoyl)glucosamine using 3-hydroxytetradecanoyl-ACP as the acyl donor. Is involved in the biosynthesis of lipid A, a phosphorylated glycolipid that anchors the lipopolysaccharide to the outer membrane of the cell. a (3R)-hydroxyacyl-[ACP] + a UDP-3-O-[(3R)-3-hydroxyacyl]-alpha-D-glucosamine = a UDP-2-N,3-O-bis[(3R)-3-hydroxyacyl]-alpha-D-glucosamine + H(+) + holo-[ACP] (3R)-hydroxytetradecanoyl-[ACP] + UDP-3-O-[(3R)-3-hydroxytetradecanoyl]-alpha-D-glucosamine = H(+) + holo-[ACP] + UDP-2-N,3-O-bis[(3R)-3-hydroxytetradecanoyl]-alpha-D-glucosamine Glycolipid biosynthesis; lipid IV(A) biosynthesis; lipid IV(A) from (3R)-3-hydroxytetradecanoyl-[acyl-carrier-protein] and UDP-N-acetyl-alpha-D-glucosamine: step 3/6. Homotrimer. Belongs to the transferase hexapeptide repeat family. LpxD subfamily.