Figure 1.

Landing folded proteins on freestanding single-layer graphene. (a) Cytochrome c (cyt c) [M+7H]⁷⁺ ions are landed normal to a freestanding single-layer graphene with a selected collision energy of 35 eV (i.e. 5 eV/charge, typical for soft-landing of molecules on a surface). (b) Folded cyt c on graphene imaged by low-energy electron holography (LEEH) showing agreement with folded cyt c computed from density functional theory (DFT). The shape of cyt c from the DFT calculations is given by the red outline obtained from the van der Waals representation of the protein. The deposition and imaging were done at room temperature.