Detecting Features of Protein Structure through their Mediator-Accessible Redox Activities

Protein function relies on sequence, folding, and post-translational modification, and molecular measurements are commonly used to reveal these structural features. Here, we report an alternative approach that represents these molecular features as readily measurable electronic patterns and validate this experimental approach by detecting structural perturbations commonly encountered during protein biomanufacturing. Specifically, we studied a monoclonal antibody standard (NISTmAb) and focused on the electronic detection of variants that have undergone interchain-disulfide bond reduction and methionine oxidation. Electronic detection of these structural perturbations is based on mediated electrochemical probing (MEP) that discerns patterns associated with the antibody's mediator-accessible redox activity. We demonstrate that MEP can rapidly (within minutes) and quantitatively transduce the protein's structural features into robust electronic signals that can enable bioprocess monitoring and control. More broadly, the ability to transduce information of a protein's molecular structure into a more convenient electronic domain offers fundamentally new opportunities to apply the power of microelectronics and real-time data analytics to chemical and biological analysis. ### Competing Interest Statement The authors have declared no competing interest.