First Liquid Protein

Proteins are in their happiest state when dissolved in an aqueous solution under physiological conditions. Without such solvent assistance, the biomolecules can't exist in a liquid state on their own—at least not until now. Adam W. Perriman and Stephen Mann of the University of Bristol, in England, and colleagues have devised the first example of a protein that can form a liquid (Angew. Chem. Int. Ed., DOI: 10.1002/anie.200903100). The team covalently attached cationic diamine groups to the surface of the protein ferritin and then took advantage of electrostatic interactions to couple anionic polymer surfactant molecules to the diamine groups. The resulting conjugate is a type of ionic liquid that remains fluid over the range of 30–405 °C. Myoglobin and lysozyme have also been successfully decorated with "hairy surfactant coronas" to produce protein melts, Mann says. Because proteins in the solid form normally skip the liquid state and sublime when heated, the fundamental work establishes a new class of biomolecular matter, the researchers say. They are hopeful that these liquidized proteins can be used in a variety of applications, including wound dressings that deliver drugs or as a solvent-free medium for green chemical synthesis.