APP-TM peptides adopt α-helical dimeric structure in SDS micelles. A. Circular dichroism (CD) spectroscopy of APP-TM peptides in the presence of 20 mM SDS at pH 7. The CD spectra of wild-type (●), V717G (○), V717F (□) and T714I (▲) show that all APP-TM peptides form similar highly helical structures in 20 mM SDS. B. Oligomeric state of APP-TM peptides at different concentrations as determined by SDS-PAGE. Wild-type APP-TM peptides were predominantly dimeric under all concentrations tested, while V717G APP-TM peptides formed monomer-dimer mixtures across the same concentration range.