EPQ: 'What are the methods and applications of genetic code expansion?'

Huge congratulations to Anwita in Year 13 who received a prestigious Gold CREST Award for her Extended Project Qualification (EPQ) thesis on DNA and genetic code expansion and the implementation of logic gates which could be crucial in the diagnosis and rapid cure of disease. Looking to ultimately pursue a career in Biomedics or Biochemistry, Anwita has undertaken her EPQ alongside her three A-levels in Biology, Chemistry and Maths.   

Specifically in her CREST Awards research project Anwita focuses on frameshifting, stop codon suppression, and sense codon reassignment, while the second part of her EPQ explores their potential to encode non-canonical amino acids and their applications, mainly in proteins and cell-signalling. Anwita’s research delved into the applications of non-canonical amino acids that were produced via genetic code expansion methods. The main uses covered were the exciting implementation of logic gates in cells, which provided an unprecedented level of control over biological processes.  

In her conclusion, Anwita summarised that molecular logic gates will be crucial in the diagnosis and rapid cure of disease. If a logic gate can be programmed, it can detect a foreign antigen of a pathogen and release antitoxins to neutralise bacteria and further stimulate an immune response. This is vital when it comes to pathogens that are difficult to detect when in the body, as they tend to ‘hide’ within cells from the immune system, e.g. the malaria-causing parasite takes cover and reproduces in red blood cells. Additionally, it’s important to remember not all major diseases are caused by different kinds of pathogens, such as atherosclerosis or diabetes, but molecular logic gates will be able to deal with them in the same way.     

These programmed by non-canonical amino acids are versatile innovations. They have the potential to improve the quality of life of patients, and contribute valuable insight about advancing gene and protein technology to scientific researchers.  

About DNA  

DNA is the universal code for all life on earth. It contains information that largely governs an organism’s traits. DNA is an extraordinary molecule because it has the power to copy itself, produce different forms of nucleic acid (RNA), and thus carry out protein synthesis. The following are some common examples of protein polymers:  

- Haemoglobin (causes red pigment in red blood cells)  

- Antibodies (produced by immune system to defend against pathogens)  

- Enzymes (act as biological catalysts to speed up chemical reactions in a cell)  

About genetic code expansion  

Genetic code expansion can be achieved by four main ways:   

1) frameshifting, which is a type of mutation allows for the tRNA (different forms of nucleic acid) to decode a quadruplet codon.   

2) stop codon suppression which allows for non-canonical amino acid incorporation instead.   

3) orthogonal translation which involved evolving an orthogonal ribosome and tRNA and related enzymes to decode a quadruplet codon.   

4) sense codon reassignment, where redundant codons are programmed to code for non-canonical amino acids.