A new method to visualize the Helicobacter pylori-associated Lewis(b)-binding adhesin utilizing SDS-digested freeze-fracture replica labeling

Freeze-fracture replica labeling has become a versatile tool to visualize b oth membrane components and other cell structures using SDS-replica cleanin g before specific immunogold labeling of proteins or lipids. We report here for the first time the adoption and optimization of the method to studies of bacterial envelopes, as applied to structural analysis of the distributi on of the unique BabA-adhesin of the gastric pathogen Helicobacter pylori. BabA is important for bacterial adherence to the human epithelial cell lini ng of the stomach. The adhesin was found to be distributed all over the bac terial cell surfaces. Our results suggest that the SDS-replica labeling all ows assessment of protein localization to distinct cell compartments and an alysis of co-localization with neighboring membrane structures.