5/27/2023 0 Comments Bound to the Alpha by Riley Trent![]() Helicobacter pylori is a gram-negative microaerophilic rod that colonizes the human stomach and infects nearly one-half of the world's population ( 34). This is the first characterization of a Kdo hydrolase involved in the modification of gram-negative bacterial LPS. Enzymatic removal of the Kdo group was dependent upon prior removal of the 1-phosphate group from the lipid A domain, and mass spectrometric analysis of the reaction product confirmed the enzymatic removal of a single Kdo residue by the Kdo-trimming enzyme. pylori capable of removing the outer Kdo sugar from Kdo 2-lipid A. In the present work we report the discovery of a Kdo hydrolase in membranes of H. pylori WaaA is a bifunctional enzyme transferring two Kdo sugars to the tetra-acylated lipid A precursor lipid IV A. ![]() ![]() ![]() However, using an in vitro assay system we demonstrate that H. Helicobacter pylori LPS has been characterized as having a single Kdo residue attached to lipid A, predicting in vivo a monofunctional Kdo transferase (WaaA). The core and O-antigen carbohydrate domains are linked to the lipid A moiety through the eight-carbon sugar 3-deoxy- d- manno-octulosonic acid known as Kdo. ![]() The lipid A domain anchors lipopolysaccharide (LPS) to the outer membrane and is typically a disaccharide of glucosamine that is both acylated and phosphorylated. ![]()
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