Abstract :
A stable homotrimeric structure for the transmembrane domain (TM) also is modeled and supported by experimental data. NMR residual dipolar couplings (RDCs) measured under three different alignment conditions are found to be incompatible with C3 symmetry.15N NMR relaxation data and RDCs show that TM is highly ordered and uninterrupted for a total length of 32 residues, extending well into the membrane proximal external region.