Figure 2. SDS-PAGE of cross-linking reaction mixtures between CaM and skMLCK peptides.

(A) Cross-linking reactions between CaM and skMLCK peptide (50-fold molar excess of BS²G, Ca²⁺ concentrations: 0 to 50 mM). As a control, CaM was diluted in water without adding buffer, EGTA, or Ca²⁺; please note the different Ca²⁺-loaded states of CaM (lane 10). (B) Cross-linking reactions between CaM and the skMLCK F19E/L31W peptide, conducted at 50-fold molar excess of SBC. Lanes 1–3: 1 mM Ca²⁺; lanes 5–7: 30 nM Ca²⁺. M: protein marker.