Figure 1. Interaction of recoverin (Rec) with the N-terminal GRK1 fragment (NRK) by BSI.

A dilution series with increasing concentration of myristoylated bovine recoverin was prepared with a constant concentration of a GST fusion protein (4 μM) containing the N-terminal 25 amino acids of bovine GRK1. In the presence of 200 μM Ca²⁺ BSI reported a K_D of 4.72 μM ± 0.72 μM (number of replicates n = 4). In the absence of Ca²⁺ (EGTA) no binding signal was observed (n = 5). BSI data was fitted to a simple one site ligand binding model to obtain the K_D value.