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Directed evolution of photosystem II for light-driven biocatalysis

Research environment

The School of Biological and Behavioural Sciences at Queen Mary is one of the UK’s elite research centres, according to the 2021 Research Excellence Framework (REF). We offer a multi-disciplinary research environment and have approximately 180 PhD students working on projects in the biological and psychological sciences. Our students have access to a variety of research facilities supported by experienced staff, as well as a range of student support services.

You will be based at QMUL’s Molecular Evolution Lab, led by Dr. Tanai Cardona. The lab’s research focuses on resolving how and when the molecular complexes of photosynthesis originated, how photosynthesis diversified through the long history of the planet, and the implications this knowledge has on the origin and early evolution of life on Earth, and beyond.

The lab also aims to harness and develop directed evolution methods, in combination with insight gained on the origin and evolution of photosynthesis, to engineer light-driven enzymes with novel properties or chemistries as future sustainable biotechnologies. The collective expertise of the Molecular Evolution Lab is at the intersection of molecular evolution, bioinformatics, genomics, biochemistry, biophysics, structural biology, and synthetic biology.

Training and development

Our PhD students become part of Queen Mary’s Doctoral College which provides training and development opportunities, advice on funding, and financial support for research. Our students also have access to a Researcher Development Programme designed to help recognise and develop key skills and attributes needed to effectively manage research, and to prepare and plan for the next stages of their career.

As a member of the Molecular Evolution Lab you will receive theoretical and practical interdisciplinary training on molecular evolution, its fundamentals and applications; in addition to trainin on microbiological, chemical, biochemical, biophysical, computational, and synthetic biology methods, towards enabling the application of directed evolution to the light-driven molecular complexes of photosynthesis. You will also have access to state-of-the-art equipment on facilities including, but not limited to, computing clusters, protein purification, MS, microscopy, genomics, structural biology, and photosynthesis research.

For more information and news on the Molecular Evolution Lab, please visit: https://cardonalab.uk/

Project description

Photosystem II, the water-splitting enzyme of photosynthesis, is one of the most powerful enzymes in biology, being entirely driven by visible light (1). You will develop and apply directed evolution methods to modify the photochemical and catalytic properties of photosystem II for potential applications in biocatalysis. There are two main ideas that you will explore, evolving photosystems that can oxidise arsenic and photosystems that can oxidise small alcohols. However, there is scope to change the type of reactions that you might want to prioritise as you find promising targets. This involves developing methods to generate mutant libraries of the core catalytic subunit of photosystem II, D1, and developing selection and high-throughput screening approaches. Successful photosystem variants will be characterised using a range of biochemical and biophysical methods.

Inorganic As(III) is a toxic element commonly found in freshwater, affecting over 150 million people worldwide. As(III) is 60 times more toxic than As(V) and water treatment, therefore, involves oxidation with methods that are expensive or difficult to deploy in the field (2). An option to develop a semi-high- to high-throughput screening tool is by adapting the classic Molybdenum-blue reaction (2,3), a chromogenic, inexpensive, and well-established method to measure As(V) concentration. Furthermore, the selective oxidation of alcohols to aldehydes or ketones has a wide range of industrial applications. New ways to improve the sustainability of these type of reactions is desired, as available methods are energy demanding, wasteful, or not environmentally friendly. An option to develop a screening tool for alcohol oxidation is by adapting fluorometric high-throughput assays on microplate readers, such as those presented in references (4,5).

This project is suitable for someone interested in photosynthesis research, as well as method development for synthetic biology and biocatalysis applications.

Funding

The studentship is funded by Queen Mary and will cover Home tuition fees, and provide an annual tax-free maintenance allowance for 3 years at the UKRI rate (£20,622 in 2023/24).

Eligibility and applying

Applications are invited from outstanding candidates with or expecting to receive a first or upper-second class honours degree in an area relevant to the project such as Biochemistry, Chemistry, Biology, Synbio, or Biotechnology. A masters degree in a relevant subject area is desirable, but not essential.

Candidates with hands-on experience on either of the following fields is also desirable, but not essential: working with cyanobacteria or photosynthesis, protein or membrane protein purifcation, genetic engineering, directed evolution, or high-throughput screening methodologies.

Applicants from outside of the UK are required to provide evidence of their English Language ability. Please see our English Language requirements page for details: https://www.qmul.ac.uk/international-students/englishlanguagerequirements/postgraduateresearch/   

Informal enquiries about the project can be sent to Dr. Tanai Cardona at t.cardona@qmul.ac.uk

Formal applications must be submitted through our online form by 31st January 2024 for consideration, including a CV, personal statement and qualifications. 

The School of Biological and Behavioural Sciences is committed to promoting diversity in science; we have been awarded an Athena Swan Silver Award. We positively welcome applications from underrepresented groups.
http://hr.qmul.ac.uk/equality/
https://www.qmul.ac.uk/sbcs/about-us/athenaswan/

Apply Online

References

  1. Oliver, T. et al. The Evolution and Evolvability of Photosystem II. Annual Review of Plant Biology 74, 225-257 (2023). https://doi.org:10.1146/annurev-arplant-070522-062509
  2. Heiba, H. F. et al. The determination of oxidation rates and quantum yields during the photocatalytic oxidation of As(III) over TiO2. Journal of Photochemistry and Photobiology A: Chemistry 424, 113628 (2022). https://doi.org:https://doi.org/10.1016/j.jphotochem.2021.113628
  3. Stauffer, R. E. Determination of arsenic and phosphous compounds in groundwater with reduced molybdenum blue. Analytical Chemistry 55, 1205-1210 (1983). https://doi.org:10.1021/ac00259a006
  4. Mei, Z. et al. High-Throughput Fluorescence Assay for Ketone Detection and Its Applications in Enzyme Mining and Protein Engineering. ACS Omega 5, 13588-13594 (2020). https://doi.org:10.1021/acsomega.0c00245
  5. Ressmann, A. K. et al. Substrate-Independent High-Throughput Assay for the Quantification of Aldehydes. Advanced Synthesis & Catalysis 361, 2538-2543 (2019).
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