Significance Plants and animals use intracellular immunity receptors, known as nucleotide-binding oligomerization domain-like receptors (NLRs), to defend themselves against invading microbes. In this study, we report the solution structure of the N-terminal coiled-coil (CC) domain from the wheat stem rust resistance protein Sr33. Remarkably, this structure differs substantially from the published crystal structure of the equivalent region from the orthologous barley powdery mildew resistance protein MLA10. Using a structural, biophysical, and functional approach, we compare the Sr33 CC domain with other structurally defined NLR CC domains. Collectively, this work redefines our current understanding of the structure and function of plant NLR CC domains, which has significant implications for future studies into this important class of defense receptors.