MICROSCOPY Vol.44▶No.2 2009
■Feature Articles: High-resolution Structural Analysis of Biological Macromolecules

High Resolution Structural Analysis of the Dynein-Microtubule Complex

Keiko Hirose and Hironori Ueno

Abstract: Dynein is a molecular motor that moves along a microtubule. Dynein interacts with a microtubule using the microtubule-binding domain at the tip of its stalk, and a predominant model for the movement involved a rotation of the stalk relative to microtubules. However, the stalk, which is a single coiled-coil, was difficult to observe in the microtubule-bound state, either by negative staining or by cryo EM. Here, using a new method “cryo-positive stain EM”, which is a combination of uranyl acetate staining and cryo EM, we succeeded in observing microtubule-bound stalks. Contrary to the above model, the stalks did not change angles relative to microtubules between the two nucleotide states we observed.

Key words: electron microscopy, image analysis, molecular motor, microtubule, dynein