Novel methods for the site selective modification of proteins
Lead Research Organisation:
University of York
Department Name: Chemistry
Abstract
Following the discovery that only 25,000 protein encoding genes exist in the human genome, it has become abundantly clear that the post-translational modification (PTM) of proteins must play a more significant role in generating the complexity of life than previously appreciated. Similarly, it is therefore conceivable that post-translational and equally chemical modification of proteins could also be employed to modulate the in-vitro function and utility of proteins, particularly by pharmaceutical companies with interests in the therapeutic and/or biotechnological applications of biologics. In this project we propose to optimize and expand studies into a range of site-selective chemical methods for bioconjugation of proteins, recently developed in the Fascione lab and initiate a collaborative project between the Chemistry and Biology Departments in York, with the overarching aim of harnessing these novel chemical modification strategies in the production of homogenously linked therapeutics.
Organisations
Studentship Projects
| Project Reference | Relationship | Related To | Start | End | Student Name |
|---|---|---|---|---|---|
| EP/N509802/1 | 01/10/2016 | 31/03/2022 | |||
| 1792596 | Studentship | EP/N509802/1 | 01/10/2016 | 30/09/2019 | Lewis Gooch |
| Description | The chemical modification of proteins is of great importance to the development of novel therapeutics as well as probing new areas of biology such as protein-protein interactions. Key challenges in the chemical modification of proteins arises from reaction requirement to complete under aqueous conditions at physiological temperature and pH as well as the multitude of functional groups present on a protein surface from various amino acids. This often leads to protein modifications that are neither site selective nor site specific. One approach to circumvent this off site attack is to introduce non-canonical functionality into the protein construct. Aldehydes are rare in nature and typically not found on protein surfaces. Aldehydes can be installed into proteins in numerous ways including n-terminal transamination of glycine with pyridoxal phosphate, sodium periodate oxidation of n terminal serine residues, as well as palladium decaging of thiazolidine motifs allowing aldehyde instalment mid-sequence. For these reasons, aldehydes present themselves as ideal candidates for the development of novel approaches to site selective and site specific chemical modification of proteins. N-heterocyclic carbenes (NHCs) have found widespread application in the cross coupling of two aldehydes. This project sought to capture this well-developed methodology and apply it to the modification of protein aldehydes. To initiate this project various NHC catalysts were screened against an aldehyde containing peptide as proof of concept. The peptide SLYRAG was synthesised via solid phase peptide synthesis (SPPS) methodology on H-Gly-2-Cltrt resin. An aldehyde was then inserted into the n-terminus of the peptide via periodate cleavage. Using NHC organocatlayst it was discovered that addition of an aldehyde containing donor could be cross coupled to an aldehyde containing peptide. Inspired by this result attention focussed on the chemical modification of myoglobin. For this, myoglobin was treated with sodium periodate which inserts an aldehyde into the n-terminal glycine via transamination. This system was used to develop the methodology required for this chemistry. Once established attention turned to modification beyond the n-terminus. Thiazolidine containing GFP was treated with Pd to unveil an aldehyde mid-sequence. Currently, detectable chemical reporters are being developed based on trial donors with aims to quantitatively modify protein. |
| Exploitation Route | Chemical biologists seeking to understand the chemistry of life, in particular the human proteome, could apply this methodology for the study of specific proteins and metabolic processes. In addition pharmaceutical companies developing antibody drug conjugates (ADCs) could use this chemistry for the synthesis of the next generation of ADCs. |
| Sectors | Pharmaceuticals and Medical Biotechnology |