Detecting features of antibody 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. We studied a monoclonal antibody standard (from the National Institute of Standards and Technology) 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 detect alterations in the antibody's structural features and produce robust electronic signals that could enable monitoring of biomanufacturing processes. The ability to transduce information regarding a protein's structural perturbations into a more convenient electronic domain offers opportunities to apply the power of microelectronics and real-time data analytics to chemical and biological analysis.