Discovery of ultrafast myosin, its amino acid sequence, and structural features
Takeshi Haraguchi, Masanori Tamanaha, K. Suzuki, Kohei Yoshimura, Takuma Imi, M. Tominaga, Hidetoshi Sakayama, Tomoaki Nishiyama, Takeshi Murata, Kohji Ito
Abstract
Significance It has been suggested for more than 50 y that the fastest myosin in the biological world with a velocity of 70 μm s −1 exists in the alga Chara , because cytoplasmic streaming with a velocity of 70 μm s −1 occurs in Chara cells. However, a myosin with that velocity has not yet been identified. In this work, we succeeded in cloning a myosin XI with a velocity of 60 μm s −1 , which was measured using a chimeric myosin. We also successfully crystallized myosin XI. Structural comparison of various myosins and mutation experiments of actin-binding regions suggests that the central regions that define the fast movement of Chara myosin XI are the actin-binding sites.