A Catch‐and‐Release Approach to Selective Modification of Accessible Tyrosine Residues

Abstract

The tyrosine side chain is amphiphilic leading to significant variations in the surface exposure of tyrosine residues in the folded structure of a native sequence protein. This variability can be exploited to give residue-selective functionalization of a protein substrate by using a highly reactive diazonium group tethered to an agarose-based resin. This novel catch-and-release approach to protein modification has been demonstrated for proteins with accessible tyrosine residues, which are compared with a control group of proteins in which there are no accessible tyrosine residues. MS analysis of the modified proteins showed that functionalization was highly selective, but reactivity was further attenuated by the electrostatic environment of any individual residue. Automated screening of PDB structures allows identification of potential candidates for selective modification by comparison with the accessibility of the tyrosine residue in a benchmark peptide (GYG).

An overview of chemo- and site-selectivity aspects in the chemical conjugation of proteins

“…More recently, Hulme and co-workers [ 253 ] developed an original catch-and-release strategy for the site-selective tagging of proteins ( figure 17 ). Using agarose beads derivatized with diazonium groups 221 , they managed to trap proteins via electrophilic aromatic substitution of solvent-accessible tyrosine residues.…”

Solid‐Phase Protein Modifications: Towards Precision Protein Hybrids for Biological Applications

“…Although the application of site‐selective modification using SP to prepare precise protein conjugates have largely been limited to PEGylation and antibody modification, such strategies clearly offer several advantages that can be expanded to other functional proteins such as enzymes to address current challenges in site‐selective protein modification and purification. With this in mind, there have been further development of several methods in the last five years [65–67] . For instance, an affinity‐based solid‐phase approach was developed for target‐selective isolation and modification of proteins such as peanut agglutinin and carbonic anhydrase II (Figure 3c) [66] .…”

“…In another study, a reactive diazonium group derived from a dianiline with a meta ‐substituted CF 3 group was incorporated onto an agarose‐based resin [67] . In this way, proteins containing surface‐accessible tyrosine group were captured onto the solid phase and underwent diazotization.…”

Virus-Based Supramolecular Structure and Materials: Concept and Prospects

“…TMV coat proteins can assemble into a monodisperse nanodisk or nanotube in vitro at pH 7.0 and pH 5.5 under suitable conditions, respectively. , Given that the VLPs are nanoscale and monodisperse, whereas the structure of VLPs can maintain the functional groups of the protein shell after assembly. In this regard, they can carry out modification within the internal or external surface and perform drug loading covalently or noncovalently in the interior or exterior. , Recently, modification of viruses and VLPs attracts much interest among researchers. In 2019, Francis and co-workers have reported excellent research in which they made a monodisperse drug delivery system by double modifications with polyethylene glycol (PEG) and doxorubicin (DOX) for a TMV disk, creating a leading work in the field of virus-based supramolecular biological assemblies.…”

“…In this regard, they can carry out modification within the internal or external surface and perform drug loading covalently or noncovalently in the interior or exterior. 22,23 Recently, modification of viruses and VLPs attracts much interest among researchers. In 2019, Francis and coworkers have reported excellent research in which they made a monodisperse drug delivery system by double modifications with polyethylene glycol (PEG) and doxorubicin (DOX) for a TMV disk, creating a leading work in the field of virus-based supramolecular biological assemblies.…”