Investigating The Effects Of Cyclisation On A Protein Tool And A Biocatalyst

Photosynthesis by plants and other photosynthetic organisms is highly efficient contributing billions of tonnes of biomass every year. In this physiochemical process, sunlight is captured by spatially and energetically organised antennae, light harvesting pigments such as chlorophyll. Once captured the energy is transferred to reaction centres in photosystems I and II where it is converted and stored in the form of chemical bonds. It is greatly desired to harvest solar energy and produce designed chemicals and/or clean fuels.

Taking inspiration from Nature, this PhD project aims to employ chemical biology and organic chemistry techniques to convert a coiled-coil protein origami (CCPO) cage into an artificial photosynthetic system for future applications. In CCPO, a single protein chain is folded along a Eulerian trail into a three-dimensional shape such as a polyhedron. The sides of the polyhedron are formed from coiled-coil (CC) dimer segments, composed of two alpha-helixes which are paired in either a parallel or antiparallel orientation. The first step in the conversion of a CCPO cage into an artificial photosynthetic system will involve the introduction of receptor sites onto the edges of the protein cage. These receptor sites will be employed for the incorporation of antennae through simultaneous dynamic covalent reactions such as disulphide exchange, boronate and acyl hydrazine formation. Similar to the natural photosynthetic system, these incorporated chromophores will have well-defined distances and orientations to allow maximum efficiency of visible light absorption and conversion. The visible light energy harvested by the antennae will be used for the production of valuable chemicals catalysed by the incorporation of a reaction centre. In summary, conversion of CCPO cages into visible light harvesting systems will be an important step towards the development of efficient artificial photosynthetic systems which can produce valuable chemicals in a clean and efficient manner. In the long run, it advances the technologies available that are capable of utilising the huge potential of solar energy as a renewable energy resource.

Catalysis is crucially important to the UK economy, with products and services reliant on catalytic processes amounting to 21% of GDP and 15% of all exports. The UK is scientifically strong and internationally recognised in the field, but the science base is fragmented and becoming increasingly specialised. The EPSRC Centre for Doctoral Training in Catalysis will overcome these problems by acting as beacon for excellent postgraduate training in Catalysis and Reaction Engineering with a programme that will develop an advanced knowledge base of traditional and emerging catalysis disciplines, understanding of industry and global contexts, and research and professional skills tailored to the needs of the catalysis researcher.

Although the chemical sector is an immensely successful and important part of the overall UK economy, this sector is not the only end-user of catalysis. Through its training and its research portfolio the Centre will, therefore, impact on a broad range of technologies, processes and markets. It will:
(a) provide UK industry with the underpinning science and the personnel from which to develop and commercially leverage innovative future technologies for the global marketplace;
(b) allow the UK to maintain its position as a world leader in the high-technology area of catalysis and reactor engineering;
(c) consolidate and establish the UK as the centre for catalysis expertise.

Likewise, society will benefit from the human and intellectual resource that the Centre will supply. The skills and technologies that will be developed within the Centre will be highly applicable to the fields of sustainable manufacture, efficient and clean energy generation, and the protection of the environment through the clean-up of air and water - allowing some of the biggest societal challenges to be addressed.