A vertebrate myosin-I structure reveals unique insights into myosin mechanochemical tuning

作者：Shuman Henry; Greenberg Michael J; Zwolak Adam; Lin Tianming; Sindelar Charles V; Dominguez Roberto; Ostap E Michael^*

来源：Proceedings of the National Academy of Sciences of the United States of America, 2014, 111(6): 2116-2121.

DOI：10.1073/pnas.1321022111

• mechanochemistry
• optical tweezers
• structural biology
• cryo-EM

Myosins are molecular motors that power diverse cellular processes, such as rapid organelle transport, muscle contraction, and tension-sensitive anchoring. The structural adaptations in the motor that allow for this functional diversity are not known, due, in part, to the lack of high-resolution structures of highly tension-sensitive myosins. We determined a 2.3-angstrom resolution structure of apo-myosin-Ib (Myo1b), which is the most tension-sensitive myosin characterized. We identified a striking unique orientation of structural elements that position the motor's lever arm. This orientation results in a cavity between the motor and lever arm that holds a 10-residue stretch of N-terminal amino acids, a region that is divergent among myosins. Single-molecule and biochemical analyses show that the N terminus plays an important role in stabilizing the post power-stroke conformation of Myo1b and in tuning the rate of the force-sensitive transition. We propose that this region plays a general role in tuning the mechanochemical properties of myosins.

• 出版日期2014-2-11