Molecular size has limited solution NMR analyses of proteins. We report (13)C-(13)C NOESY experiments on a 480 kDa protein, the multi-subunit ferritin nanocage with gated pores. By exploiting (13)C-resonance-specific chemical shifts and spin diffusion effects, we identified 75% of the amino acids, with intraresidue C-C connectivities between nuclei separated by 1-4 bonds. These results show the potential of (13)C-(13)C NOESY for solution studies of molecular assemblies >100 kDa.