Inhibition of Neisseria meningitidis Group X N‐Acetylglucosamine‐1‐Phosphotransferase by Donor Substrate Analogues

Abstract

Neisseria meningitidis is a major cause of bacterial meningitis in the meningitis belt of Sub‐Saharan Africa. N. meningitidis serogroup X is increasing prevalence in the meningitis belt. The capsular polysaccharide is a homopolymer of (α1‐4)‐linked N‐acetyl‐D‐glucosamine (GlcNAc)‐1‐phosphate. We have shown that the enzyme responsible for formation of this polymer is a GlcNAc‐1‐phosphotransferase that catalyzes the transfer of a GlcNAc‐1‐phosphate from UDP‐GlcNAc to the 4‐hydroxyl of a terminal GlcNAc‐1‐phosphate on the growing polysaccharide chain.In this investigation we explore its interaction with substrates analogs of the sugar nucleotide donor, UDP‐GlcNAc. Recently a sugar nucleotide inhibitor was described for glycosyltransferases based on a proposed conformation change induced by donor binding. We demonstrated that several of these novel analogs of UDP‐GlcNAc are indeed inhibitors. The best inhibitors contained a bulky thien‐2‐yl group at the 5‐positon of uracil.UDP‐GalNAc, which differs from the UDP‐GlcNAc only by the orientation of the sugar 4‐hydroxyl group, and UDP‐Glc, which differs by the absence of an acetamido group were neither substrates nor inhibitors suggesting that the 4‐hydroxyl and the 2‐acetamido may be important for interaction of the sugar moiety. Both UDP‐trifluoroacetylglucosamine and UDP‐azidoacetylglucosamine were good inhibitors of GlcNAc‐1‐phosphoryltransferase, confirming the importance of the acetamido group.