Practice question

Circular dichroism interpretation relies on spectral region. Far-ultraviolet region from 190 to 250 nanometers dominated by backbone amide transitions provides secondary structure information on helices and sheets. Near-ultraviolet region from 250 to 320 nanometers originates from aromatic residues of tryptophan, tyrosine, phenylalanine and disulfides held rigidly in chiral tertiary environment, offering tertiary structure information. Tryptophan emission reports solvent polarity via fluorescence, not dichroism. Beta-sheet twist influences far-ultraviolet shape. Near-ultraviolet CD thus correctly pairs with tertiary structure assessment in folding studies.