Abstract
H. pylori is a gram-negative and microaerophilic bacterium found in human stomach. It infects more than 50% of the world population and increases the risk of developing gastric ulcer and stomach cancer. The standard first-line is a one week “triple therapy” but an increasing number of infected individuals are found to harbor antibiotic-resistant bacteria. It is important to find a new treatment or antibacterial drug targets to H. pylori. Coenzyme A (CoA) biosynthesis pathway is a good antimicrobial drug target to inhibit H. pylori infection because Coenzyme A is an essential cofactor in synthesis of oxidation of fatty acid for all living organisms. Phosphopantetheine adenylyltransferase (PPAT) is the rate-limiting enzyme involved in this pathway. Understanding the PPAT catalytic mechanism is important for drugs design. The structure of H. pylori PPAT has been determined recently. I had used the site-directed mutagenesis to identify the critical residues take part in enzyme catalysis by kinetic analysis. It provided important information about those critical residues when designing drugs.