Engineering biosynthesis and incorporation of an immunogenic amino acid

Live bacterial vaccines can be engineered to more effectively trigger a desired immune response to prevent infection. This project examines an approach to making more effective live bacterial vaccines by engineering the bacteria to introduce certain atypical protein building blocks, called non-native amino acids (NNAAs), into their proteins. These NNAAs could help stimulate an immune response against proteins in bacteria that would usually evade the immune response, thus leading to more effective vaccines.

As part of this project, undergraduate students will receive mentoring and resources to conduct projects related to non-standard amino acids.

Metabolic engineering strategies will be utilized to create a de novo biochemical pathway that forms a nitroaromatic amino acid. The nitro chemical functional group has scarcely been explored as a product of metabolic engineering. Therefore, the stability and toxicity of relevant nitro compounds will be explored.

In parallel, the substrate specificity of engineered aminoacyl-tRNA synthetase and tRNA pairs will be examined in order to facilitate template-directed incorporation of this amino acid within proteins. This project will also study whether the immunogenic amino acid can be introduced to a model bacterial antigen without disrupting key structural features, and how the mouse immune system responds to the modified and unmodified antigen.

Overall, this project will generate foundational knowledge and tools that may lead to the first application of metabolic engineering to vaccine research.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.