SAXS STUDIES OF THE BACTERIAL CELL WALL

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The cell wall is a fundamental structure of the bacterial cell. This Gigadalton-sized macromolecular meshwork encases the entire cell and protects bacteria from mechanical stress. Indeed, antibiotics that interfere with cell wall synthesis or turnover cause the cell to lyse due to the high (ca. 3 atm.) internal osmotic pressure. Bacterial cell walls were examined by small angle solution x-ray scattering a few decades ago, but with much less bright sources (rotating anodes), and in a dehydrated state. These experiments suggested that bacterial cell walls are non-periodic. New data, however, suggest they are periodic. We are in the midst of trying to resolve the question by electron cryotomographic techniques, but wish to complement these studies with SAXS. We believe the powerful modern synchrotrons may reveal significantly more detail about short-range order than was obtained earlier, which would differentiate and refine the existing models of cell wall structure.