Effect of ethylene glycol on the interaction of different myosin subfragment 1.cntdot.nucleotide complexes with actin

Biochemistry ◽  
1989 ◽  
Vol 28 (15) ◽  
pp. 6478-6482 ◽  
Author(s):  
Ednan Mushtaq ◽  
Lois E. Greene
Keyword(s):  
Ethylene Glycol ◽  
Myosin Subfragment ◽  
Myosin Subfragment 1

scholarly journals Evidence for the two-step binding of ATP to myosin subfragment 1 by the rapid-flow-quench method

1983 ◽  
Vol 209 (3) ◽  
pp. 617-626 ◽  
Author(s):  
T E Barman ◽  
D Hillaire ◽  
F Travers
Keyword(s):  
Ethylene Glycol ◽  
Myosin Atpase ◽  
Experimental Conditions ◽  
Binding Process ◽  
Atp Concentration ◽  
Myosin Subfragment ◽  
Rapid Flow ◽  
Myosin Subfragment 1 ◽  
Ph Decrease ◽  
Quench Method

1. The initial steps on the myosin ATPase (EC 3.6.1.3) pathway are taken to be: (formula; see text) A two-step binding for ATP is assumed, but the evidence for it is unconvincing; because of the rapidity of the process unambiguous values for K1 and K2 are not available. 2. We investigated the myosin mechanism by the chemical flow-quench technique. Reaction mixtures containing [gamma-32P]ATP plus myosin subfragment 1 were quenched in unlabelled ATP (ATP chase) or acid (Pi burst). 3. We show that the ATP-chase method can lead directly to unambiguous values for K1 and k+2. 4. The binding process was slowed down by 40% ethylene glycol. It was studied as a function of the ATP concentration. A limiting plateau resulted, showing a two-step binding for ATP, and values for K1 and k+2 were obtained. 5. K1 and k+2 are rather sensitive to the experimental conditions. Ethylene glycol and lowering of the pH decrease both constants, but an increase in KCl concentration increases them. This suggests that the binding of ATP to myosin is of an electrostatic nature. 6. The Pi-burst method can lead directly to k+3 + k-3, but under certain conditions the kinetics are governed by K1 and k+2. This uncertainty of the interpretation of Pi-burst experiments is discussed.

scholarly journals Modification of the interactions of myosin with actin and 5′-adenylyl imidodiphosphate by substitution of ethylene glycol for water

1984 ◽  
Vol 217 (1) ◽  
pp. 169-177 ◽  
Author(s):  
S B Marston ◽  
R T Tregear
Keyword(s):  
Ethylene Glycol ◽  
Dissociation Rate ◽  
Detectable Effect ◽  
Muscle Fibres ◽  
Skeletal Muscle Myosin ◽  
Specific Effects ◽  
Myosin Subfragment ◽  
Myosin Subfragment 1 ◽  
Glycerinated Muscle ◽  
Myosin X

We studied the effect of replacing water by ethylene glycol as solvent on the properties of skeletal muscle myosin, myosin subfragment-1 (S1) and heavy meromyosin. Ethylene glycol (50%, v/v) had no detectable effect on the affinity of myosin or actomyosin for the substrate analogue 5′-adenylyl imidodiphosphate (AMPPNP). However, the rate constants for formation and dissociation of the myosin X MgAMPPNP complex were reduced 200-fold; the logarithm of the dissociation rate was roughly proportional to the fractional concentration of ethylene glycol. Nucleotide dissociation was accelerated at least 300-fold by pure actin but remained slow with regulated actin in the absence of Ca2+. Ethylene glycol substitution reduced the affinity of S1 and the S1 X MgAMPPNP complex for actin equally (100-fold at 50% ethylene glycol). These results show that ethylene glycol has specific effects on myosin's enzymic mechanism, which can account for its effect on the tension and stiffness of glycerinated muscle fibres.

Structure of Myosin Subfragment-1 from Electron Microscopy and Crystallography

1988 ◽  
Vol 46 ◽  
pp. 156-157
Author(s):  
Donald A. Winkelmann
Keyword(s):  
Electron Microscopy ◽  
Molecular Weight ◽  
Actin Filaments ◽  
Light Chains ◽  
Myosin Filament ◽  
Primary Role ◽  
Heavy Chains ◽  
Myosin Subfragment ◽  
Myosin Subfragment 1 ◽  
Globular Head

The primary role of the interaction of actin and myosin is the generation of force and motion as a direct consequence of the cyclic interaction of myosin crossbridges with actin filaments. Myosin is composed of six polypeptides: two heavy chains of molecular weight 220,000 daltons and two pairs of light chains of molecular weight 17,000-23,000. The C-terminal portions of the myosin heavy chains associate to form an α-helical coiled-coil rod which is responsible for myosin filament formation. The N-terminal portion of each heavy chain associates with two different light chains to form a globular head that binds actin and hydrolyses ATP. Myosin can be fragmented by limited proteolysis into several structural and functional domains. It has recently been demonstrated using an in vitro movement assay that the globular head domain, subfragment-1, is sufficient to cause sliding movement of actin filaments.The discovery of conditions for crystallization of the myosin subfragment-1 (S1) has led to a systematic analysis of S1 structure by x-ray crystallography and electron microscopy. Image analysis of electron micrographs of thin sections of small S1 crystals has been used to determine the structure of S1 in the crystal lattice.

scholarly journals Studies of Ligand-induced Conformational Perturbations in Myosin Subfragment 1

1989 ◽  
Vol 264 (18) ◽  
pp. 10810-10819
Author(s):  
K N Rajasekharan ◽  
M Mayadevi ◽  
M Burke
Keyword(s):  
Myosin Subfragment ◽  
Myosin Subfragment 1
Sign in / Sign up

Export Citation Format

Share Document