Ca(2+)-saturated calmodulin binds to double-length IQ lever-arm sequences from murine myosin-V, forming a 1:1 "bridging" complex with very high affinity, (K9d)<10 pM for double motifs, IQ34, IQ45 and IQ56). Such a 1:1 complex involves interaction of one calmodulin (CaM) molecule with two adjacent IQ-motifs, providing a molecular mechanism for the observed Ca(2+)-dependent CaM dissociation from ...

Anterior torque control during retraction is difficult to achieve with lingual orthodontic treatment. This article describes the use of a lever-arm and mini-implant system as absolute anchorage for controlled retraction of the anterior teeth during lingual orthodontic treatment and evaluates 2 protrusion cases treated with this system. Various clinical situations are discussed and analyzed from...

Myosin VI is a processive myosin that has a unique stepping motion, which includes three kinds of steps: a large forward step, a small forward step and a backward step. Recently, we proposed the parallel lever arms model to explain the adjacent binding state, which is necessary for the unique motion. In this model, both lever arms are directed the same direction. However, experimental evidence ...

Myosins are molecular motors that exert force against actin filaments. One widely conserved myosin class, the myosin-Vs, recruits organelles to polarized sites in animal and fungal cells. However, it has been unclear whether myosin-Vs actively transport organelles, and whether the recently challenged lever arm model developed for muscle myosin applies to myosin-Vs. Here we demonstrate in living...

In the present paper, we described our attempt to characterize the rough three-dimensional features of the structural analogue of the key intermediate of myosin's cross-bridge cycle. Using quick-freeze deep-etch replica electron microscopy, we observed that actin-attached myosin during in vitro sliding was bent superficially as postulated by the conventional hypothesis, but in the opposite dire...

It is unclear whether the reverse-direction myosin (myosin VI) functions as a monomer or dimer in cells and how it generates large movements on actin. We deleted a stable, single-α-helix (SAH) domain that has been proposed to function as part of a lever arm to amplify movements without impact on in vitro movement or in vivo functions. A myosin VI construct that used this SAH domain as part of i...

Myosin VI supports movement toward the (-) end of actin filaments, despite sharing extensive sequence and structural homology with (+)-end-directed myosins. A class-specific stretch of amino acids inserted between the converter domain and the lever arm was proposed to provide the structural basis of directionality reversal. Indeed, the unique insert mediates a 120 degrees redirection of the lev...