Catalyzes the transfer of the L-Ara4N moiety of the glycolipid undecaprenyl phosphate-alpha-L-Ara4N to lipid A. The modified arabinose is attached to lipid A and is required for resistance to polymyxin and cationic antimicrobial peptides. 4-amino-4-deoxy-alpha-L-arabinopyranosyl di-trans,octa-cis-undecaprenyl phosphate + lipid IVA = lipid IIA + di-trans,octa-cis-undecaprenyl phosphate. Optimum pH is 6.5. Lipopolysaccharide metabolism; 4-amino-4-deoxy-beta-L-arabinose-lipid A biosynthesis. Induced by BasR. Belongs to the glycosyltransferase 83 family.