Selective protein complexation and coacervation by polyelectrolytes

•Protein selectivity can be achieved by polyelectrolyte solely through electrostatics.•Selective binding is influenced by protein charge anisotropy, protein binding affinity, polyelectrolyte characters, and polyelectrolyte assembling.•Correlation between protein binding affinity and phase separation is evaluated.

This review discusses the possible relationship between protein charge anisotropy, protein binding affinity, polymer structure, and selective phase separation. We hope that a fundamental understanding of primarily electrostatically driven protein-polyelectrolyte (PE) interactions can enable the prediction of selective protein binding, and hence selective coacervation through non-specific electrostatics. Such research will partially challenge the assumption that specific binding has to be realized through specific binding sites with a variety of short-range interactions and some geometric match. More specifically, the recent studies on selective binding of proteins by polyelectrolytes were examined from different assemblies in addition to the electrostatic features of proteins and PEs. At the end, the optimization of phase separation based on binding affinity for selective coacervation and some considerations relevant to using PEs for protein purification were also overviewed.

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