Schematic illustration of our approach to using high resolution electron tomography (center) to bridge the gap between 3D images of bacterial cells acquired at optical resolution (top left) with atomic structures of chemotaxis receptors obtained using X-ray crystallography (bottom right).
For more details see Lefman et al (2004).

We are taking a multi-pronged approach towards these goals. Thus, we have initiated studies to establish a systematic catalog of types of multi-protein assemblies that occur in bacterial cells engineered to express signaling components in high concentrations. We are determining the three-dimensional shapes of stable multi-protein complexes formed between different members of the signaling apparatus using cryo electron microscopy of frozen hydrated specimens of purified protein complexes. We are crystallizing receptors in the plane of the membrane in the presence and absence of signaling components to use electron crystallographic approaches to generate plausible atomic models for the membrane assemblies and multi-protein complexes by positioning known high-resolution structures of the individual components into the EM-derived density maps. In addition, we have initiated whole cell imaging studies of plunge-frozen (i.e. vitrified s spensions) wild-type E.coli and a variety of mutants, with the goal of describing the cellular architecture of the entire apparatus in terms of the various sub-assemblies.