A highly virulent strain of the fungal pathogen wheat Stem Rust, designated UG99, has proven to be pathogenic on 90% of commercial wheat cultivars worldwide. Recently, a wheat resistance (R) gene, Sr33, was demonstrated to provide valuable resistance to UG99 when introgressed into hexaploid wheat. The nucleotide-binding (NB) and leucine-rich repeat (LRR) domains of plant resistance proteins share reasonable homology to that of the mammalian nucleotide-binding oligomerisation domain (NOD)-like proteins (NLRs). While structural data exists for some mammalian NLRs, the molecular mechanisms behind plant NLR protein-mediated resistance are still poorly understood. This study aims is to perform a structure/function analysis of the wheat NLR, Sr33. To achieve these aims, several constructs of the Sr33 gene have been generated, selecting for key functional domains within the protein. These constructs have been tested in two expression systems; Escherichia coli and Pichia pastoris. To date, the N-terminal coiled-coil (CC) signaling domain and central NB activation domain of the Sr33 protein have been purified. This was achieved through a combination of nickel-affinity and size exclusion chromatography, for the purpose of obtaining protein of a high purity, necessary for biophysical and structural studies. Herein we present a preliminary structural and biophysical characterisation of the N-terminal Coiled-coil signaling domain of Sr33.