Curvature of Buckybowl Corannulene Enhances Its Binding to Proteins

Corannulene, a polycyclic aromatic hydrocarbon, has garnered much attention on account of its promising applications in high-performance electronics. Investigations of its potential biological applications have, however, remained hitherto scarce. In the present contribution, to explain the distinctive interaction of the geodesic corannulene with proteins, the adducts formed by lysozyme (LSZ) and two carbon materials, namely, corannulene:LSZ and perylene:LSZ, were prepared and investigated using a variety of experimental and computational approaches. We find that LSZ binds the two ligands at its active site, forming stable complexes. Interestingly, although corannulene and perylene have very similar structures, standard binding free-energy calculations demonstrate that the former possesses a much greater binding affinity for LSZ compared with the latter, which can be ascribed to its three-dimensional pi-bowl curvature and unique charge distribution, enhancing its electrostatic interaction with LSZ. Corannulene is found to be more effective than perylene in inhibiting the protein activity. In addition, corannulene hardly affects the fluorescence of LSZ. The present work indicates that endowed with a curved pi-surface and large dipole moment, corannulene is a promising ligand, capable of binding a broad range of proteins through a variety of intermolecular interactions, modulating their biological or catalytic activity, yet not affecting their fluorescent properties.