DETERMINATION OF SOLVENT ACCESSIBILITY OF AROMATIC AMINO-ACID-RESIDUES IN PROTEINS USING 2ND DERIVATIVES UV ABSORPTION-SPECTRA

A new method was developed for determining solvent accessibility of ty rosine and tryptophan residues in proteins from the wavelengths of pea ks in the second derivatives of the UV absorption spectra. Analytical relations to calculate the number of shielded and exposed amino acid r esidues in the protein globule were derived from a mathematical model worked out previously for spectral changes observed in transitions bet ween shielded and exposed states of the residues. Sixteen proteins wer e examined by this method. The results were in good agreement with lit erature data.