Peptides and DNA are two of the most commonly used self-assembling biological molecules for the construction of nanomaterials. However, there are only a few examples that combine these two self-assembly motifs as key structural elements in a nanostructure. We report on the synthesis of a peptide-DNA conjugate that self-assembles into a stable homotrimer based on the coiled-coil motif. The hybrid peptide-DNA trimer was then used as a novel three-way junction to link together either small DNA tile nanostructures, or to close up a triangular wireframe DNA structure. The resulting nanostructures were characterized by atomic force microscopy, and compared with a scrambled, non-assembling peptide as a control. These hybrid nanostructures enable the integration of peptide motifs and potentially bio-functionality with DNA nanostructures, and open the door to novel nano-materials that have the advantages of both molecules.