Lipopolysaccharide (LPS) is a major component of outer membrane which is consisted of lipid A-core (oligosaccharide) on both inner and outer region and O-antigen (known as distal repeating unit with four sugars: N-acetylglucosamine, glucose, rhamnose and galactose). O-antigen is part of three domains of LPS, which is attached to lipid A-core; however, O-antigen and lipid A-core are synthesized separately. In this pathway, synthesis of three of O-antigen sugars is demonstrated. UDP-α-D-galactose is converted to UDP-D-Galacto-1,4-furanose by facilitation of UDP-galactopyranose mutase. dTTP glucose-1-phosphate is derivatized to dTDP-rhamnose. Fructose-6-phosphate gains an amino group, incorporates an acetate moiety and then acquires a nucleoside diphosphate resulting in UDP-N-acetyl-D-glucosamine.

O-Antigen Building Blocks Biosynthesis References