Understanding Bacterial Cell Division Proteins Using Novel Nanoencasulation Methods

Membrane proteins represent an estimated 30% of gene transcripts in the natural world and more than 40% of drug targets, yet they remain underrepresented in structural biology. Membrane proteins are challenging targets for structural characterisation for many reasons. Unlike soluble proteins, which are suspended in a continuous aqueous environment, membrane proteins are housed in an environment displaying multiple characteristics across its breadth. To ensure native function of these proteins ideally this complex environment must be preserved. In our laboratory we have recently developed a new system which, for the first time, allows membrane proteins to be used as components in synthetic biology systems. The system produces a novel hybrid nano-particle that contains the membrane protein surrounded by its native lipid environment, all stabilised by a simple organic polymer. The whole particle takes the form of a 10 nm sized disc (SMALP) that stabilises the membrane protein to allow it to be used in biophysical and biochemical characterisation methods. To date, SMA has successfully been used to purify a number of membrane proteins while retaining native-like activity, including AcrB, KcsA and ABC transporters.

Of particular interest for study are the membrane proteins involved in bacterial cell division. These proteins often do not have a counterpart in eukaryotic cells and they are essential for the survival of the bacteria. Consequently, bacterial cell division proteins are more and more recognized as potential new antibiotic targets. Therefore, the use of the novel SMA encapsulation method to purify these proteins for biophysical, biochemical and structural characterisation could supply important information about this system and potential targets for antibiotic therapy. Further to this, the project hopes to investigate the use of SMA to capture complexes within the membrane into disc in order to study them by the above methods.