Fig. 4
The major determinants governing high affinity binding and non-catalytic inhibition of SFKs reside in the segment containing the kinase domain of Chk. a A schematic illustration depicting the arrangements of functional domains in Csk, Chk and the Csk-Chk chimera. The black dotted line on the SH2-kinase linker of Csk-Chk chimera denotes the junction joining the sequences of Csk and Chk. The sequence at the junction of the chimera as well as those at the corresponding segment of Csk and Chk are shown. b Enzymatic activity of Hck (2PA-YEEI) in the presence and absence of the designated concentrations of Chk or Csk-Chk chimera. c Sensorgrams showing the kinetics of interactions of Csk-Chk chimera with the immobilized Hck (2PA-YEEI). The red arrow indicates the point when buffer was introduced to initiate dissociation of Csk-Chk chimera from the complex formed by Csk-Chk chimera and the immobilized Hck (2PA-YEEI). d Molecular binding activities of Csk-Chk chimera at the designated concentrations. e Comparison of the association rate constant (k a ), dissociation rate constant (k d ) and equilibrium constants of dissociation (KD) of Chk, Csk-Chk chimera and Csk. The kinetic parameters of binding of Csk and Chk to Hck (2PA-YEEI) are also shown in Fig. 3f