Protein-directed self-assembly of a fullerene crystal.
Publication Type:Journal Article
Source:Nat Commun, Volume 7, p.11429 (2016)
Keywords:Amino Acid Sequence, Binding Sites, Crystallography, X-Ray, Fullerenes, Molecular Sequence Data, Peptides, Protein Binding, Protein Multimerization, Protein Structure, Secondary, Protein Structure, Tertiary, Solutions, Static Electricity
<p>Learning to engineer self-assembly would enable the precise organization of molecules by design to create matter with tailored properties. Here we demonstrate that proteins can direct the self-assembly of buckminsterfullerene (C60) into ordered superstructures. A previously engineered tetrameric helical bundle binds C60 in solution, rendering it water soluble. Two tetramers associate with one C60, promoting further organization revealed in a 1.67-Å crystal structure. Fullerene groups occupy periodic lattice sites, sandwiched between two Tyr residues from adjacent tetramers. Strikingly, the assembly exhibits high charge conductance, whereas both the protein-alone crystal and amorphous C60 are electrically insulating. The affinity of C60 for its crystal-binding site is estimated to be in the nanomolar range, with lattices of known protein crystals geometrically compatible with incorporating the motif. Taken together, these findings suggest a new means of organizing fullerene molecules into a rich variety of lattices to generate new properties by design.</p>