A biochemical and biophysical analysis of a ubiquitous protein translocation apparatus

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An ancient and essential development for life on Earth has been the evolution of a thin film of lipids that surround and form each cell. These membranes provide a barrier to water and hydrophilic solutes. They serve to isolate biological reactions from the outside, and offer the potential to separate charge and to communicate & aggregate with one another to form complex structures. More complicated cells also contain internal membrane structures that provide a further division for chemical reactions and generation of electric potentials. These events facilitated the ability to harness energy and to develop and maintain the complex structures and biochemistry of the cell. The necessary exchange of materials across lipid membranes between the outside and different compartments gives rise to a transport problem for small and large molecules alike. Proteins are large polymers of amino acids made according to the genetic code of each respective gene in the cell cytosol. In order to perform their specific roles many of them need to be delivered to alternative locations. This requires that they pass either across or into a specific membrane. This proposal aims to learn more about this important process using the bacterial cell membrane as a model system. The apparatus responsible for protein movement across membranes has been purified. Once prepared, various parts will then be labelled with chemical reagents that are able to report on their environment by the way that they interact with light. These probes will characterise the movements that the components make as they transport proteins across the membrane, which will aid our understanding of this reaction. New findings in this area will have implications in the understanding of protein secretion, cell biogenesis and development. Moreover, they will also help us understand other molecular machines and more general processes such as membrane transport. This information might be also exploited toward the development novel antibiotics.