The laboratory works on two remarkable supramolecular assemblies involved in bacterial chemotaxis. Dynamic receptor arrays generate an integrated signal in response to multiple stimuli that results in either increased or decreased activity of an associated kinase. Transient kinetic analysis based on flash photolysis of caged chemoeffectors is being used to investigate the in vivo architectural dynamics of the receptor arrays, guided by a high-resolution structural model of receptor-receptor interactions. An ultra-sensitive motor switching response is produced upon receipt of the chemotactic second messenger, a small phosphoprotein. A 3D model of the motor switch complex is being constructed based on single particle analysis of electron microscope images. These studies should aid development of strategies for elucidation of the design principles of the macromolecular assemblies involved in signal transduction in cell biology.
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