Myosin analysis

Parry, D. A. D. (1981). Structure of rabbit skeletal myosin Analysis of the amino acid sequences of two fragments from the rod region./. Mol. Biol. 153, 459-464. 

Some work has been completed on reaction of proteins with nitrite followed by hydrolysis and analysis for amino acids It has been shown that 3-nitrotyrosine and 3,4-dihydroxyphenylalanine are formed from bovine serum albumin when nitrosation occurs under conditions similar to those found in the human stomach (36), Direct demonstration that nitrite reacts with protein has been made by using NaN02 with bovine serum albumin (pH 5.5, 20 C and 200 ppm nitrite). A 60% loss of the originally added nitrite was observed in one week and nearly half of the nitrite (labelled %) could be recovered from the protein. Similar work with myosin revealed that 10-20% of the incorporated label was present as 3-nitrotyro-sine (J7). 

The fifth was a molecular biologist, who smiled sweetly and pointed out that all the others had missed the point. The frog jumps because of the biochemical properties of its muscles. The muscles are largely composed of two interdigitated filamentous proteins, actin and myosin, and they contract because the protein filaments slide past each other. This property of the actin and myosin is dependent on the amino acid composition of the two proteins, and hence on chemical, and thus on physical properties. In the last analysis, the molecular biologist insisted, following James Watson, we are all nothing but subatomic particles. 

Mamar-Bachi, A. Cox, J.A. Quantitative analysis of the free energy coupling in the system calmodulin, calcium, smooth muscle myosin light chain kinase. Cdl Calcium 1987, 8, 473-482. 

In contrast to milk, where samples are primarily derived from cows, meat analysis has to be performed in samples of a widely different animal origin including cattle, lamb, swine, poultry, and fish. Muscle is a complex matrix with a pH of 5.7, composed of muscle fibers, various types of connective tissue, adipose tissue, cartilage, and bones. Sarcoplasmic proteins such as myoglobin, and glycolytic enzymes are soluble in water while the myofibrillar proteins such as myosin and actin are soluble in concentrated salt solutions (14). The connective tissue proteins, collagen and elastin, are insoluble in both solvents. 

The myofibrillar proteins make up 50-60% of the total protein of muscle cells. Insoluble at low ionic strengths, these proteins dissolve when the ionic strength exceeds -0.3 and can be extracted with salt solutions. Analysis of isolated mammalian myofibrils86 shows that nine proteins account for 96% or more of the protein myosin, which constitutes the bulk of the thick filaments, accounts for 43% and actin, the principal component of the thin filaments, 22%. 

Myosins II from other sources have similar structures. For example, analysis of the DNA sequence for a heavy chain gene from the nematode Caenorhabditis showed that the protein contains 1966 residues, 1095 of which contain an amino acid sequence appropriate for a 160-nm long coiled coil.123 There are no prolines within this sequence, which lies between Pro 850 and... 

Ruiz-Trillo, I., Paps, J., Loukota, M., Ribera, C., Jondelius, U., Baguna, J. and Riutort, M. (2002) A phylogenetic analysis of myosin heavy chain type II sequences corroborates that Acoela and Nemertodermatida are basal bilaterians. Proceedings of the National Academy of Sciences USA 99, 1 1246-11251. 

Fragments of natural coiled coils, even when they are of considerable size, rarely fold [see, for example, Trybus et al (1997) for an analysis of the myosin rod]. This may well serve a biological purpose, since a coiled coil the size of myosin might find it difficult to reach its proper register if local coiled-coil interactions formed rapidly and randomly along the... 

Ruppel, K. M., and Spudich, J. A. (1996). Structure-function analysis of the motor domain of myosin. Annu. Rev. Cell Dev. Biol. 12, 543-573. 

Fig. 18C. (B) Cross-sectional views of the three crowns of the EM 3D map shown in E. (C) Cross-sectional views of the densities between the crowns of the EM 3D map shown in E. (D) Stereo view of the X-ray model of Fig. 18C reconstructed to 50 A resolution. (E) Stereo view of the 3D reconstruction of the myosin filament structure obtained by single particle analysis using the classes shown in Fig. 19C (from Al-Khayat et ai, 2005a). The...

Al-Khayat, H. A., Morris, E. P., Powell, A. S., Kensler, R. W., and Squire,J. M. (2005a). 3D structure of vertebrate (fish) muscle myosin filaments by single particle analysis. 

Oshima, K., Takezawa, Y., Sugimoto, Y., Kiyotoshi, M., and Wakabayashi, K. (2003). Modeling analysis of myosin-based meridional X-ray reflections from frog skeletal muscles in relaxed and contracting states. Adv. Exp. Med. Biol. 538, 243-249. 

Much is known about the steps in the biochemical reaction of ATP breakdown by myosin and how these relate to the production of force by the crossbridge. However, since it is no longer attached to the myosin thick filament, myosin SI cannot be an adequate model for a strained crossbridge. Thus data from muscle fibers (e.g., the dependence of phosphate affinity on strain) must also be considered. In this review we attempt to summarize the currently known structural data on myosin and produce a synthesis of this with the biochemical data. We start with an analysis of the polymorphism of the myosin crossbridge and relate this to the crossbridge cycle proposed by Lymn and Taylor (1971). 

Coluccio, L. M., and Geeves, M. A. (1999). Transient kinetic analysis of the 130-kDa myosin I (MYR-1 gene product) from rat liver. A myosin I designed for maintenance of tension /. Biol. Chem. 274, 21575-21580. 

Kovacs, M., Malnasi-Csizmadia, A., Woolley, R. J., and Bagshaw, R. J. (2002). Analysis of nucleotide binding to Dictyostelium myosin II motor domains containing a single tryptophan near the active site./. Biol. Chem. 277, 28459-28467. 

Kurzawa-Goertz, S. E., Perreault-Micale, C. L., Trybus, K. M., Szent-Gyorgyi, A. G., and Geeves, M. A. (1998). Loop I can modulate ADP affinity, ATPase activity, and motility of different scallop myosins. Transient kinetic analysis of SI isoforms. 

In thinking about X-ray diffraction from this assembly, a number of the sarcomere components contribute to the observed patterns in ways that have been the subject of detailed analysis. In the A-band, these include the myosin filament backbone, where the coiled-coil a-helical myosin rods pack together, the myosin head arrays in the bridge regions of the myosin filaments, the non-myosin A-band proteins titin and C-protein (MyBP-C), and the A-band parts of the actin filaments. Very little has been seen in X-ray patterns so far that appears to be related to the M-band, probably... 

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