Probing the structure of the cytoplasmic domain of the aspartate receptor by targeted disulfide cross-linking

Applying the technique of targeted disulfide cross-linking to the cytoplasmic domain of the aspartate receptor of Salmonella typhimurium indicates a generally alpha-helical conformation of the linker region, and a close juxtaposition and a parallel alignment at the interface between the two subunits in the linker region. This conclusion is supported by the results from the Fourier transform of the hydrophobicity values of the amino acid sequences. Aspartate binding in the periplasmic domain causes a closer juxtaposition of the two subunits in the cytoplasmic domain, as indicated by the more rapid disulfide cross-linking on addition of aspartate.