Infrared Laser Desorption and Electrospray Ionisation of Non‐Covalent Protein Complexes: Generation of Intact, Multiply Charged Species. Issue 1 (26th January 2021) - Kooijman, Pieter C.
Abstract: We present a novel method enabling the infrared laser desorption and electrospray ionisation (ESI) of protein complexes in their native state. Using this method, we demonstrate the surprising generation of intact, multiply charged ions of myoglobin, non‐covalent haemoglobin complex, and intact immunoglobulin G antibody in their native states. The observation of a surviving population of intact non‐covalent complexes is characteristic of the low internal energy build‐up experienced during both laser desorption from solution and subsequent ionisation. Compared to conventional nano‐ESI, this approach yielded slightly lower average charge states suggesting additional maintenance of tertiary structure during desorption and ionisation, and is more tolerant to salts enabling simpler sample purification procedures. This approach may enable the development of high‐throughput native‐MS methods capable of analysing the composition and sequence of multiple macromolecular samples per minute. Abstract : The surprising generation of intact, multiply charged ions of non‐covalent haemoglobin complex and intact immunoglobulin G antibody in their native state is shown by using an optimized laser ablation electrospray ionisation method. The survival of intact non‐covalent complexes shows low internal energy build up during laser desorption and ionisation. Lower average charge states than conventional nano‐ESI were observed, suggesting additional maintenance of tertiary structure. The method is also more tolerant to salts, enabling simpler sample purification procedures.