Catalyzes the N-acylation of UDP-3-O-myristoylglucosamine using 3-hydroxyarachidoyl-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 (Probable). 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] Bacterial outer membrane biogenesis; LPS lipid A biosynthesis. Homotrimer. Belongs to the transferase hexapeptide repeat family. LpxD subfamily.