Testing the substrate flexibility of Helicobacter pylori's pseudaminic acid biosynthetic pathway

Abstract

Helicobacter pylori infection is the leading cause of duodenal ulcers and gastric cancer worldwide. We are developing an antibiotic strategy based on the presence of the unique sugar pseudaminic acid (PseNAc) on H. pylori but not on human cells. PseNAc is essential for formation of functional flagella on H. pylori, and H. pylori that lack the ability to make PseNAc are avirulent. In our two‐step strategy, we will (1) hijack H. pylori's PseNAc biosynthetic pathway with azidosugars, then (2) covalently deliver therapeutic compounds to azide‐covered H. pylori via Staudinger ligation to perturb the pathogens. For this strategy to be viable, H. pylori's PseNAc biosynthetic pathway must be permissive of azide‐containing substrates. Here we set out to examine the substrate flexibility of PseNAc biosynthetic enzymes by comparing in vitro kinetic data of natural versus azide‐containing substrates. We present our initial data expressing PseNAc biosynthetic enzymes, preparing azide‐containing substrates, and testing the substrate flexibility of the PseNAc biosynthetic pathway in vitro. Support was provided by the James Stacy Coles Foundation, HHMI, and Dreyfus Foundation.