Self-assembling peptides can be used to create tunable higher-order structures for the multivalent presentation of a variety of ligands. We describe a novel, fiber-forming coiled-coil-based peptide that assembles to display, simultaneously, carbohydrate and peptide ligands recognized by biomacromolecules. Preassembly decoration of the scaffold with a diphtheria toxin peptide epitope or a mannose motif did not interfere with self-assembly of the nanostructure. The resulting multivalent display led to tighter binding by antidiphtheria toxin antibodies and mannose-specific carbohydrate binding proteins, respectively. The potential of this self-assembling peptide to display ligands in bioanalytical assays is illustrated by its decoration with a disaccharide glycotope from the Leishmania parasite. Carbohydrate-specific antibodies produced in response to a Leishmania infection are detected more sensitively in human and canine sera due to the multivalent presentation on the self-assembled scaffold. Thus, nanofibers based on coiled-coil peptides are a powerful tool for the development of bioassays and diagnostics.