Movements of Truncated Kinesin Fragments with a Short or an Artificial Flexible Neck

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 94; no. 14; pp. 7275 - 7280
• Main Authors: Inoue, Yuichi, Toyoshima, Yoko Yano, Iwane, Atsuko Hikikoshi, Morimoto, Sayuri, Higuchi, Hideo, Yanagida, Toshio
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences of the United States of America 08.07.1997; National Acad Sciences; National Academy of Sciences; The National Academy of Sciences of the USA
• Subjects: Amino acids; Animals; Binding sites; Biochemistry; Biological Sciences; Biophysics; Drosophila; Drosophila melanogaster; Genes; Gliding; Head; Kinesins - chemistry; Microtubules; Molecules; Peptide Fragments - chemistry; Physics; Protein Conformation; Recombinant Proteins - chemistry; Stiffness; Velocity
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.94.14.7275

To investigate the role of the neck domain of kinesin, we used optical trapping nanometry to perform high-resolution measurements of the movements and forces produced by recombinant kinesin fragments in which the neck domains were shortened or replaced by an artificial random coil. Truncated kinesin fragments (K351) that contain a motor domain consisting of ≈ 340 aa and a short neck domain consisting of ≈ 11 aa showed fast movement (800 nm/s) and 8-nm steps. Such behavior was similar to that of recombinant fragments containing the full-length neck domain (K411) and to that of native kinesin. Kinesin fragments lacking the short neck domain (K340), however, showed very slow movement (<50 nm/s), as previously reported. Joining an artificial 11-aa sequence that was expected to form a flexible random chain to the motor domain (K340-chain) produced normal fast (≈ 700 nm/s) and stepwise movement. The results suggest that the neck domain does not act as a rigid lever arm to magnify the structural change at the catalytic domain as has been believed for myosin, but it does act as a flexible joint to guarantee the mobility of the motor domain.