Catalyzes the phospholipid dependent N-acylation of the N-terminal cysteine of apolipoprotein, the last step in lipoprotein maturation (PubMed:2032623, PubMed:21676878, PubMed:28885614, PubMed:28675161). Utilizes a two-step reaction via a ping-pong mechanism (PubMed:21676878, PubMed:28675161). Lnt undergoes covalent modification in the presence of phospholipids, resulting in a thioester acyl-enzyme intermediate. It then transfers the acyl chain to the amine group of the N-terminal diacylglyceryl-modified cysteine of apolipoprotein, leading to the formation of mature triacylated lipoprotein (PubMed:21676878, PubMed:28675161). In vitro, can utilize the phospholipids phosphatidylethanolamine (PE), phosphatidylglycerol (PG), phosphatidic acid (PA) or cardiolipin (CL) (PubMed:2032623, PubMed:21676878). PE is the most efficient acyl donor (PubMed:21676878). a glycerophospholipid + N-terminal S-1,2-diacyl-sn-glyceryl-L-cysteinyl-[lipoprotein] = a 2-acyl-sn-glycero-3-phospholipid + H(+) + N-acyl-S-1,2-diacyl-sn-glyceryl-L-cysteinyl-[lipoprotein] Protein modification; lipoprotein biosynthesis (N-acyl transfer). Monomer. Essential. Depletion induces juxtapositioning of inner and outer membranes and alters the architecture of the cell envelope. It causes mislocalization of outer membrane lipoproteins (PubMed:15513925). The mutant has a copper-sensitive, temperature sensitive phenotype (PubMed:1938881). Belongs to the CN hydrolase family. Apolipoprotein N-acyltransferase subfamily.