Table 1 of Singh, Mol Vis 2009; 15:2050-2060.

Table 1. Comparison of binding constants of Cu2+-αA-crystallin interactions determined by fluorescence spectroscopy and isothermal titration calorimetry.

Protein Kd(app) Kd(real)
Fluorescence ITC Fluorescence ITC
αA-crystallin 6.4×10−6 12.0×10−6 16.6×10−12 31.2×10−12
G98R αA-crystallin 9.8×10−6 4.7×10−6 25.5×10−12 12.2×10−12

The Kd(app) from fluorescence quenching studies was obtained as described in the Methods section. The overall dissociation constant, Kd(app), from ITC results was calculated from the association constants (see legends to Figure 2) using the formula, Kd=[1/(K1*K2*K3*….Kn)1/n]. Since the observed Kd(app) is the net result of competition between Cu2+-protein interaction and Cu2+-glycine interactions, Kd(real) was estimated as described previously [37] as the product of Kd(app) and the first dissociation constant of Cu(Gly)2 (2.6×10−6 M).

Singh, Mol Vis 2009; 15:2050-2060. http://www.molvis.org/molvis/v15/a220

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