Some regularities of dynamic accessibility of buried fluorescent residues to external quenchers in proteins

Incorporation of Melittin into phosphatidylcholine bilayers

“…A decrease Of KQ is therefore attributed to a decrease of k, corresponding to a lower accessibility of the Trp residue. In a aqueous solution of monomeric melittin, the Trp residue is highly accessible by NO~ (KQ = 51.3 mol -x) very similar to the case of an aqueous solution ofindole (KQ = 48 mo1-1) [16]. A solution of tetrameric melittin in water shows a reduced accessibility of the Trp residue (KQ = 28.3 mol-a), due to the aggregation and/or conformational change.…”

Fluorescence Quenching Reactions

“…This quencher also seems to cause certain proteins to precipitate. Listings of several less efficient quenchers have been given by Steiner and Kirby (1969), Bushueva et al (1975), Altekar (1977), and Bohorquez et al, (1984). Quenchers listed in Table I seem to quench primarily by a closerange interaction (collision).…”

Viscosity dependence of protein dynamics

“…Experimentally, the influence of solvent viscosity on protein dynamics has repeatedly been studied. Apart from myoglobin, which has been well investigated in different studies, [1][2][3][4][5][6][7] an effect of solvent viscosity has also been observed for buried tryptophanes 8,9 and for carboxypeptidase. 10 A conformational change of phenyl-benzyl-nitroxides may be induced by the solvent.…”