Myosin motor domain

Smith, C. A., Rayment, 1. X-ray structure of the magnesium (11). ADP-vanadate complex of the Dictyostelium discoideum myosin motor domain to 1.9 A resolution. Biochemistry 35 5404-5407, 1996. 

Fisher, A., Smith, C., Thoden, J., et al., 1995. X-ray structures of die myosin motor domain of Dietyostelium diseoideumcomplexedMth MgADP BeFx and MgADP AlF4. Biochemistry 34 S960-S972. 

Gulick, A. M., Bauer, C. B., Thoden, J. B., and Rayment, I. (1997). X-ray structures of the MgADP, MgADPgammaS, and MgAMPPNP complexes of the Dictyostelium discoideam myosin motor domain. Biochemistry 36, 11619-11628. 

Dominguez, R., Freyzon, Y., Trybus, K. M., and Cohen, C. (1998). Crystal structure of a vertebrate smooth muscle myosin motor domain and its complex with the essential light chain Visualization of the pre-power stroke state. Cell 94, 559-571. 

Malnasi-Csizmadia, A., Kovacs, M., Woolley, R. J., Botchway, S. W., and Bagshaw, C. R. (2001). The dynamics of the relay loop tryptophan residue in the Dictyostelium myosin motor domain and the origin of spectroscopic signals. /. Biol. Chem. 276, 19483-19490. 

Uyeda, T. Q., Abramson, P. D., and Spudich, J. A. (1996). The neck region of the myosin motor domain acts as a lever arm to generate movement. Proc. Natl. Acad. Sri. USA 93, 4459-4464. 

Heavy lifting. A single myosin motor domain can generate a force of approximately 4 piconewdons (4 pN). How many times its "body weight" can a myosin motor domain lift Note that 1 nevHon = 0.22 pounds. Assume a molecular mass of 100 kd for the motor domain. 

After death, the ratio of ADP to ATP increases rapidly. In the ADP form, myosin motor domains bind tightly to actin. Myosin-actin interactions are possible because the drop in ATP concentration also allows the calcium concentration to rise, clearing the blockage of actin by tropomyosin through the action of the troponin complex. 

Mechanochemical Coupling in Molecular Motors Insights from Molecular Simulations of the Myosin Motor Domain... 

Yu, H. B., Ma, L., Yang, Y., and Cui, Q. (2007) Meehanochemieal eoupling in the myosin motor domain. I. Insights from equilibrium aetive-site simulations, Plos Comput. Biol. 3, 199-213. 

Figure 1.5. The waters of Thales of the myosin II motor. Stereo views of the crystal structure of the myosin motor domain of Dictostelium discoidium in presence of ATP are shown. A Space-filling display showing water molecules on a sculptured surface of the myosin II motor. B Those water molecules throughout the entire structure that are sufficiently fixed in space to be seen by X-ray diffraction are...

Especially when seen in three dimensions, as in Figure 1.5 A, the stereo view of the myosin motor domain has the appearance of a sculpted surface. The surface contains crevices and depressions, as though formed from sandstone that had been weathered by wind and rain. Only a relatively few water molecules are seen in these surface recesses, because the majority of water molecules are too mobile to be observed by X-ray diffraction. Yet these surface crevices and depressions can be filled with water molecules that, by the consilient mechanism, contribute to the energy considerations of motor function. In this regard, it should be appreciated that only 10% to 20% of the existing water molecules are sufficiently fixed in space to be located by X-ray diffraction. ... 

C.B. Bauer, H.M. Holden, J.B.Thoden, R. Smith, and I. Rayment, X-ray Structures of the Apo and MgATP-bound States of Dictostelium dis-coidium Myosin Motor Domain. / Biol. Chem., 275, 38494-38499,2000. 

M. Suzuki, J. Shigematsu, Y. Fukunishi, Y. Harada, and T. Yanagida, T. Komada, Coupling of Protein Surface Hydrophobicity Change to ATP Hydrolysis by Myosin Motor Domain. Biophys. J., 71,18-23,1997. 

Abstract Actomyosin is a natural nanomachine which generates a force up to 5pN per skeletal myosin motor domain and moves at a speed of 10 jum s The working stroke per skeletal myosin motor domain per ATP hydrolysis was evaluated as at least 60 nm by Yanagida et al. (1985 Nature 316 366-369) which lead to the loose coupling model of Oosawa and Hayashi (1986 Advances in Biophysics 22 151-183). 

A dynamic change of the surface hydrophobicity of the myosin motor domain during the ATP hydrolysis... 

Fig. 2a, b Image of hydration structure of myosin motor domain, a Oxygen (red), nitrogen (green), hydrocarbons (gray), CONH bonds (black), b Water on polar atoms (cyan), water on hydrophobic atoms (violet)... 

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