Practice question

Far-ultraviolet circular dichroism provides rapid low-sample assessment of secondary structure based on chiral exciton coupling of amide chromophores. Disulfide constrained α-helical peptide exhibits hallmark double negative minima at 208 and 222 nanometers and positive peak near 193 nanometers, confirming helical integrity and oxidative folding. Ultraviolet absorption alone shows only aromatic contributions without conformational signature. Mass spectrometry verifies mass not fold. Nuclear magnetic resonance requires higher concentration and extensive assignment. CD therefore optimally screens synthetic helical peptides stabilized by disulfide bridges.