This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The coiled-coil protein interaction motif is frequently used to control macromolecular interactions in biology and materials science. To identify new heterospecific coiled-coil interactions we measured the complete pair-wise interactions of 48 synthetic coiled coils and 7 human bZIP coiled-coils. From this 55 x 55 protein interaction matrix, we identified 27 pairs of peptides that preferentially heterodimerize. These 27 pairs can be used to construct many interaction subnetworks of 3-6 nodes that exhibit interesting interaction patterns. Of special interest are pairs that participate in mutually orthogonal interactions, and solution and structural characterization of two sets of orthogonal pairs was carried out. The orthogonal pair, and other network motifs from our screen, will provide new capabilities in synthetic biology and other applications.