Our research interests

Our general interests

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We are interested in how the molecular machines of the cell assembles, functions, and evolves. To tackle this problem we use electron cryo-tomography, a technique that enables us to visualize this machinery inside living cells -- to resolutions capable of discerning individual proteins. The technique involves flash-freezing the specimen then imaging it over a range of angles in an electron microscope. The resulting images can then be used to detemine the 3-D structure of the specimen in a manner directly analogous to CT or CAT scans. We interpret our imaging results in the light of molecular phylogenetics to understand the evolutionary context of different molecular machines. Bacteria and archaea are the biological subjects of our studies: their (relative) simplicity make them ideal subjects for study of basis biological principles, yet with considerable practical application in, for example, antibiotic development or sustainable re-utilization. To better understand evolution of molecular machinery we currently focus on a family of machines called type III secretion systems as a case study. Type III secretion systems function as nanoscale “3-D printers” to assemble one of two larger molecular machines: bacterial flagella and injectisomes. Bacterial flagella are nanoscale motors that spin helical filaments to act as a propellor for the bacterium, while injectisomes are nanoscale "syringes" that puncture host cells and pump toxic effector proteins into them. Nevertheless, the core type III secretion system found in both of flagella and injectisomes makes it clear that they are ancestrally related, making it an exciting case study to understand molecular evolution. We are also particularly interested in a number of curious variants of the flagellum that we recently identified, as these differences promise to shed light upon some basic principles of assembly, function, and evolution.