L-4-Aminoarabinose-bactoprenyl phosphate

L-4-Aminoarabinose-bactoprenyl phosphate (L-4-Aminoarabinose-BP) serves as a substrate for the ArnT enzyme, playing a key role in the covalent modification of lipid A. It facilitates the transfer of L-4-aminoarabinose (Ara4N) to the lipid A segment of lipopolysaccharides (LPS), enabling the cationic modification of lipid A and thus conferring resistance to cationic antimicrobial peptides (CAMPs) in Gram-negative bacteria. This endogenous intermediate is synthesized intracellularly by a series of enzymes encoded by the arn operon, such as ArnC and ArnD, in Gram-negative organisms like Escherichia coli.