Cholesteryl-6-O-acyl-α-d-glucopyranoside of Helicobacter pylori relate to relative lysophospholipid content

The presence of cholesteryl glucosides and high levels of lysophospholipids are elements making the cell wall of Helicobacter pylori unique. In this study, we have investigated the relationship between lysophospholipid content and cholesteryl glucoside composition of variants of 6 clinical isolates. The samples were characterized by diverse outer membrane phospholipase A activity measured as lysophospholipid content of the cell wall. A pldA negative mutant was also included in the study. Thin-layer chromatography showed that cholesteryl glucosides were present in all samples. However, the distribution of cholesteryl-6-O-acyl-α-d-glucopyranoside, cholesteryl-α-d-glucopyranoside and cholesteryl-6-O-phosphatidyl-α-d-glucopyranoside varied according to lysophospholipid content. Cholesteryl-6-O-acyl-α-d-glucopyranoside was exclusively observed in the isolates/variants with an intact pldA and where a significant amount of lysophospholipids could be demonstrated. High lysophospholipid content destabilizes membranes. The balance between cholesteryl-6-O-acyl-α-d-glucopyranoside, cholesteryl-α-d-glucopyranoside and cholesteryl-6-O-phosphatidyl-α-d-glucopyranoside in H. pylori is probably important for the stability of the membrane when the lysophospholipid content varies.