Morphology and Protein Composition of Gas Vesicles from Wild Type and Gas Vacuole Defective Strains of Halobacterium salinarium Strain 5

Abstract

The morphology and protein composition of gas vesicles isolated from wild-type and gas vacuole defective (gvdef) isolates of Halobacterium salinarium strain 5 have been analysed. Two general vesicle shapes were found: spindles, and cylinders with short biconical ends. Wild-type strains contained a majority of spindle-shaped vesicles (94 %), while 69% of the vesicles in gvdef strains were cylindrical. Electrophoretic analysis of gas vesicle proteins showed that vesicle preparations contained only a single major protein species. In addition, the polypeptide in vesicles from the gvdef strain migrated more slowly than that from the wild-type strain. From the rates of electrophoretic migration, the molecular weights of gas vacuole proteins in the wild-type and gvdef strains were estimated as 16 800 and 18200, respectively. Data provided here are consistent with the suggestion that polypeptide processing may be involved in the formation and assembly of gas vesicles in Halobacterium.