IN-SITU LOCALIZATION OF THE 60-K PROTEIN OF HELICOBACTER-PYLORI, WHICH BELONGS TO THE FAMILY OF HEAT-SHOCK PROTEINS, BY IMMUNOELECTRON MICROSCOPY

The groEl homologue of Helicobacter pylori was isolated and characterized by means of immunoelectron microscopy, after cryosectioning. The 60 k protein was isolated from Helicobacter pylori by treatment of the cells with 2-butanol and purified by anion exchange chromatography. The native molecular weight of the 60 k protein was estimated to be 420 k by size exclusion chromatography. The purified 60 k protein showed the typical rotational symmetry of chaperonins when analyzed by electron microscopy. Ultrathin sections of Helicobacter pylori were immunostained by a polyclonal antibody directed against the hsp-65 of Mycobacterium tuberculosis. The label revealed a clustered localization of the 60 k protein on the cell surface as well as in the periplasmic space.