Table 1.
Dissociation Constants for Ca2+ Binding to S100A4
| [EF1] (μM) | [EF2] (μM) | |
|---|---|---|
| S100A4 (low salt) | 54.4 ± 10.8a | 3.3 ± 1.3a |
| S100A4 (high salt) | >500b | 2.6 ± 1.3b |
| S100A4 and MIIA1851–1960 (high salt) | 3.6 ± 0.2c | 0.26 ± 0.01c |
a
The dissociation constants for Ca2+ binding to each S100A4 EF-hand domain were determined by ITC under low-salt conditions [20 mM Tris (pH 7.5), 20 mM KCl, and 250 μM TCEP].
b
These values are from published studies (71). The dissociation constants for Ca2+ binding to each S100A4 EF-hand domain were determined using a 5,5′Br2-BAPTA competition assay under high-salt conditions [20 mM Tris (pH 7.5), 150 mM KCl, 1 mM DTT, and 0.02% NaN3].
c
The dissociation constants for Ca2+ binding to each S100A4 EF-hand domain in the presence of MIIA1851–1960 were determined using a 5,5′Br2-BAPTA competition assay under high-salt conditions [20 mM Tris (pH 7.5), 150 mM KCl, 1 mM DTT, and 0.02% NaN3].