Plants contain a vast amount of sugar. Sugar is important because it can be fermented by microorganisms into ethanol which can be used as a fuel – a commodity that we are running out of. Biofuels are already being produced, but they are largely derived from crops that could be better utilized as food sources. A significant challenge is, therefore, ensuring that we move towards a more sustainable solution by making use of the large amount of sugar that is found in the inedible parts of plants which currently goes to waste. These sugars are locked away in polysaccharides, the most abundant of which is cellulose. Cellulose is a highly crystalline substance formed from β-1,4-linked glucose subunits and is incredibly difficult to break down. There is therefore considerable effort being expended on finding an efficient means of deconstructing cellulose so that sugar contained within can be used to generate bioethanol – the use of enzymes represents a highly promising approach to accomplishing this goal.
Recently a new family of enzymes has been identified which play a key role in cellulose degradation, both in industry and in nature. These are the lytic polysaccharide monooxygenases, or LPMOs. LPMOs are copper dependent oxygenases, which introduce chain breaks into cellulose thereby augmenting the activity of glycoside hydrolases which mediate the majority of cellulose deconstruction. A key aspect of LPMO biochemistry, is that they require not only copper and oxygen to function, but also an electron source. The identity of the electron source in bacteria remains unknown. We have identified a range of proteins encoded by bacterial genomes that appear to contain carbohydrate binding modules appended to domains with possible electron transporting functions that we have termed the X-domains. The aim of this studentship is to characterize a subset of these domains both structurally and biochemically to gain an understanding of the role that these proteins play in nature. The ultimate aim is to use the knowledge gained in enzyme engineering approaches to derive more efficient enzymatic systems to be used in the biorefinery.
1) Characterise the structures and enzymatic activities of X-domains to ascertain whether they might support LPMO activation.
2) An understanding of the molecular interactions and redox processes involved in LPMO activation.
Techniques you will learn and use:
- Molecular biology and protein production in Escherichia coli.
- X-ray crystallography for determining structures of proteins, enzyme-substrate and/or enzyme-cofactor complexes.
- Electrochemistry and EPR as appropriate to investigate redox states of cofactors.
- Enzyme assays.
- Biophysical techniques such as isothermal titration calorimetry, surface plasmon resonance and microscale thermophoresis as appropriate.
Informal enquiries can be made to Dr Glyn Hemsworth via email: [email protected]
Further information about postgraduate studies in Leeds can be found here: http://www.fbs.leeds.ac.uk/gradschool
Applications should include a cover letter, CV and contact details of two referees.
The studentship will provide fees at the UK/EU level, plus a stipend at research council level (£14,296 per year), for three years.
Due to funding restrictions, we are only able to accept candidates from UK and the EU. Members of the European Economic Area (EEA) are also eligible.
Candidates are expected to have, or be on track to obtain, an undergraduate degree at 2.1 level or above in a relevant subject.
If English is not your first language you will need to meet our language requirements outlined here: http://www.fbs.leeds.ac.uk/postgraduate/researchdegree.php#tab3