The T cell antigen receptor (TCR) is an eight-subunit membrane-embedded receptor complex that controls T cell activation. Upon encountering peptide:MHC ligand presented on antigen-presenting cells, the ligand-binding TCRαβ heterodimer transmits intracellular signals via the dimeric signal-transducing modules, CD3εδ, CD3εγ and ζζ. These four modules are held together within the complex through electrostatic interactions in the transmembrane domains (TMD). Despite the central role of this receptor in adaptive immunity, the mechanism by which ligand binding is transmitted across the membrane still remains poorly understood. This study aims to gain a more complete structural understanding of the full receptor complex with the goal of providing insights into possible mechanisms of signalling through transmembrane conformational changes. To this end, I performed a cysteine-scanning approach, testing more than 500 cysteine mutant combinations from a library of more than 150 individual TMD cysteine mutants of TCR complex. I identified several disulphide crosslinks that enable the mapping of each subunit within the receptor complex. To experimentally define the helical limits of these TMD sequences, I produced TM peptides of TCRα, TCRβ, CD3δ and CD3γ for nuclear magnetic resonance (NMR) spectroscopy-based analysis of their structural content. Collectively, these biochemical and biophysical data will be utilised to calculate a model of TCR complex that will enable a more targeted approach to study mechanisms of TCR triggering.