Electron diffraction studies of the peptidoglycan of bacterial cell walls

Peptidoglycan of the gram-positive bacterium Lactobacillus plantarum was adsorbed onto hydrophilic crystalline films of graphitic oxide. Destruction by radiation damage was reduced by using a device which permitted scanning of the specimen for several hours through a focussed electron beam of low current density (2.5 X 10(-5) A/cm2). In additition to the sharp Debye-Scherrer rings caused by graphitic oxide, peptidoglycan causes a diffuse Debye-Scherrer ring in the region of 4.5 A. This can be interpreted as the packing periodicity of the peptidoglycan within the planes of the peptidoglycan sacculi.