In contrast, such polar residues are not found in the human SGT1 protein. In the polar region of the human SGT1 protein, there is a phenylalanine residue and other residues that are not conserved. At the end of the TPR domain, there are two charged residues that are absent in the human SGT1 protein: the first charged residue is substituted in the human homolog by glycine, and the second by serine. These sequence substitutions could destabilize the C-terminal part of the TPR domain and prevent dimerization of the human SGT1. A mutagenesis study conducted on AtSGT1b identified only one mutation in the TPR domain, Glu119Gly, which results in a dominant-negative phenotype in the immune response to the PXV virus, mediated by the NB-LRR receptor Rx in Nicotiana benthamiana. The dimerization of the SGT1 protein is most likely functionally important, but its role in plants has to be experimentally proven. In the current study, the structure of the full-length barley SGT1 protein in solution has been determined. As can be expected from a 4-(Benzyloxy)phenol flexible multidomain protein, all three structural domains behave independently. FPS-ZM1 similar observations were made when the results of the NMR structural studies of the isolated domains and the full-length human SGT1 protein were compared. Although the exact molecular mechanism of SGT1��s action is not known, many biochemical studies have revealed that SGT1 most likely interacts with other proteins by linking different protein complexes. For example, the SGT1 protein interacts with ubiquitin ligase complexes and with heat shock proteins. Through dimerization, the SGT1 protein could provide a functional connection between protein degradation and chaperone stabilization of the inactive/active conformation of protein complexes. Using molecular docking and modeling techniques, we predict a possible dimerization model of the barley SGT1 TPR domains. Although structures of TPR dimers, even with a similar closed topology, have been reported, they all have a hydrophobic rather than a polar or charged interface.