In Fig. 5 we show a typical titration curve of pentalysine interacting with a planar lipid membrane of diphytanoyl phosphatidylserine (DPhPS) lipids. Potentials in Fig. 5 are measured on the cis side relative to trans. The plot shows the compensation voltages necessary to hold the membrane at...
ThepKa values measured for calcium saturated calmodulin ranged between 9.5 (Lys 75) and 10.2 (Lys 13); two residues (Lys 94 and Lys 13) showed a biphasic titration curve suggesting their possible involvement in ion-pairs. The dynamic behavior of the lysine side chains was deduced from spin ...
The initial K i value is then used to focus a second FP titration at TCI concentrations below initial K i to estimate the crucial second-order rate constant k inact /K I . Linear regression on the F b versus time graph will give the rate of change of F b, which is converted into ...
Although the pKa value of the lysine ϵ-amine in solution is ∼10.5, molecular dynamics simulations by Zhang and Bruice (25, 26) indicate that this value diminishes to 8.2 upon formation of the SET7/9 Michaelis complex due to the proximity of the AdoMet sulfonium cation and the low ...
8B). The computed Glu-184 titration curves suggest that protonation of this residue is indeed very sensitive to the side chain position in the binding site. To assess the importance of Glu-184, we replaced this residue with glutamine, a neutral analog of glutamate, and with alanine, to ...
6 and this work), and its low pKa favors formation of the thiolate anion, which is a more powerful nucleophile than the protonated form. These important functions of DJ-1 in protein repair reduce the probability (although do not eliminate it) of an important role for cysteine 106 oxidation ...
The chemical shift of this resonance was studied over the pH range 3 to 11, and the titration curve showed two inflection points, at pH 5.7 and 9.0. The higher pKa, designated pKa1, was assigned to the ionization of the lysyl residue itself while the pKa of 5.7, designated pKa2, was ...