Huxley

Huxley A F 1957 Muscle structure and theories of contraction Prog. Biophys. Biophys. Chem. 7 255... 

J. N, Murrell, S. Carter, S. C. Farancos, P. Huxley, and A. J, C. Varandas, Molecular Potential Energy Functions, John Wiley Sons, Tnc., Chichester, 1984. 

Huxley, A.F., Simmons, R. Proposed mechanism of force generation in striated muscle. Nature 233 533-538, 1971. 

FIGURE 17.12 Electron micrograph of a skeletal muscle myofibril (in longitndinal section). The length of one sarcomere is indicated, as are the A and I bands, the H zone, the M disk, and the Z lines. Cross-sections from the H zone show a hexagonal array of thick filaments, whereas the I band cross-section shows a hexagonal array of thin filaments. (Photo courtesy of Hugh Huxley, Brandeis University)... 

Through the British Association, Thomson and his associates offered a powerful rival reform program to that of metropolitan scientific naturalists (including T. H. Huxley and John Tyndall) who promoted a professionalized science, free from the perceived shackles of Christianity and grounded on... 

The proposed model for the so-called sodium-potassium pump should be regarded as a first tentative attempt to stimulate the well-informed specialists in that field to investigate the details, i.e., the exact form of the sodium and potassium current-voltage curves at the inner and outer membrane surfaces to demonstrate the excitability (e.g. N, S or Z shaped) connected with changes in the conductance and ion fluxes with this model. To date, the latter is explained by the theory of Hodgkin and Huxley U1) which does not take into account the possibility of solid-state conduction and the fact that a fraction of Na+ in nerves is complexed as indicated by NMR-studies 124). As shown by Iljuschenko and Mirkin 106), the stationary-state approach also considers electron transfer reactions at semiconductors like those of ionselective membranes. It is hoped that this article may facilitate the translation of concepts from the domain of electrodes in corrosion research to membrane research. 

The voltage sensor is the part of a channel protein responsible for detection of the membrane potential. A voltage sensor of the voltage-dependent Na+ channel was predicted by Hodgkin and Huxley in 1952. Positively charged amino acid residues in S4 of each repeat play an essential role as the voltage sensor. 

Studies on muscle contraction carried out between 1930 and 1960 heralded the modem era of research on cytoskeletal stmctures. Actin and myosin were identified as the major contractile proteins of muscle, and detailed electron microscopic studies on sarcomeres by H.E. Huxley and associates in the 1950s produced the concept of the sliding filament model, which remains the keystone to an understanding of the molecular mechanisms responsible for cytoskeletal motility. 

Huxley, H.E. Hanson, J. (1960). The molecular basis of contraction in cross-straited muscle. In Structure and Function of Muscle (Bourne, G.H., ed.), Vol. I, pp. 183-227. Academic Press, New York. 

Huxley, A.F. Niedergerke, R. (1954). Structural changes in muscle contraction. Interference microscopy of living muscle fibres. Namre 173, 971-973. 

Huxley, H.E. (1973). Muscular contraction and cell motility. Nature 243,445-449. 

A.F. Huxley s 1957 Theory Further Structural Approaches Hugh Huxley s 1969 Theory Transient Mechanical Properties Velocity Transients Tension Transients... 

In his theory, A.F. Huxley suggested that a myosin crossbridge attaches to actin and produces an amount of force which is proportional to the amount of strain on the crossbridge, that is to the amount by which it is distorted (Figure 5). He also suggested that crossbridges were only able to attach over a range of preferred distortions. From these basic ideas he derived mathematical expressions for force... 

This theory was also able to explain the energetic properties of muscle. Hill had found in 1938 that the heat produced by a muscle was proportional to the shortening distance and Huxley was able to derive this relationship from his mathematical expressions. However, Hill found later (Hill, 1964), that the rate of energy output did not increase at a constant rate as the velocity increased, as he had originally found, but declined at high velocities. This could not be explained by Huxley s 1957 theory. 

X-ray diffraction of live muscle (H.E. Huxley and Brown, 1967) showed the structure of the thick and thin filaments and how they changed when the muscle contracted, or was put into rigor (in rigor muscle, ATP is absent from the muscle. 

Huxley suggested that crossbridges can move out in this way and bind to actin because S-2 of HMM acted as a flexible link between LMM in the thick filament backbone and S-1. This was based on the observation that heavy meromyosin could be digested by chymotrypsin into two further subffagments (Lowey et al., 1966), S-1 and S-2, as described above, and that S-1 contained the ATPase and actin binding sites, whereas S-2 did not moreover, S-2 did not self-aggregate, as did the rod or LMM portion of myosin. 

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