Practice question

Interpreting absorption and fluorescence fingerprints distinguishes protein composition and tryptophan localization. Protein containing only tyrosine lacks tryptophan, showing λmax near 274 nm, low extinction and emission ~303 nm, designated X. Proteins containing tryptophan exhibit additional 280 nm absorption. Solvent-exposed tryptophan on protein surface contacts water, undergoes full solvent relaxation, emitting near 350-355 nm representing Y. Buried tryptophan within hydrophobic core experiences nonpolar environment restricting relaxation, emitting blue-shifted around 308-335 nm representing Z. Correlating A280, λem and quenching allows assignment of X as only Tyr, Y surface Trp, Z buried Trp.