Fig. 7. Effects of Alanine mutations of basic residues in R1800-K1810 of the GTD on inhibitory activity of the GTD. The dissociation constants of GST-GTD and M5HMM, obtained by a quadratic fit, are 0.058 mM (WT), 0.103 mM (R1800A), 0.071 mM (R1805A/R1807A), 0.028 mM (R1809A), and 0.0438 mM (K1810A). (A and B) in this Figure are the same as A and I, respectively, in Fig. 5.

Fig. 8. Sequence alignment of the GTD of mouse myosin Va (Mm 5a), rat myosin Vb (Rn 5b), human myosin Vc (Hs 5c), and yeast Myo2p (Sc Myo2). Pink, conserved acidic residues; cyan, conserved basic residues; gray, other conserved residues. Open arrowheads indicate K1706 and K1779 which are essential for the inhibitory activity of the GTD. Asterisks indicate the basic residues in R1800-K1810 of mouse myosin Va. Underlines show the a-helixes in the crystal structure of the GTD of yeast Myo2p. The number in the parentheses indicates the residue number in the crystal structure of the GTD of yeast Myo2p (2f6h.pdb).

Fig. 9. Conserved basic residues in the crystal structure of the GTD of Myo2p, a yeast myosin V. (A) Structural overview of the GTD. Blue, subdomain-I; yellow, subdomain-II. (B) Conserved basic residues that located on the surface of the GTD. The numbers in parentheses indicate the residues in the GTD of mouse myosin Va.

Fig. 10. Model for the interaction between the GTD and the motor domain of myosin Va in the prepower stroke conformation. The GTD-binding pocket in the motor domain consists of the N-terminal domain (blue), converter (orange), and the essential light chain (cyan) in IQ1. Subdomain-II (yellow) of the GTD interacts with the motor domain. The numbers in parentheses indicate the residues in the crystal structure of the GTD of yeast Myo2p. ELC, essential light chain; RLC, regulatory light chain. (Left) Overview. (Right) Close-up view.