Melting of myosin rod as revealed by electron microscopy. I. Effects of glycerol and anions on length and stability of myosin rod.
The length of the rods of intact myosin molecules and of isolated myosin rods were determined under a variety of conditions by electron microscopy. In all experiments, except for freeze-drying, the temperature and pH were kept at 20 degrees C and 7.0. Glycerol was found to have a marked effect on the stability of myosin especially for air-dried molecules. In the presence of 0.3 M of volatile buffer salts, e.g., ammonium acetate, -formate, -benzoate, -bicarbonate, -carbamate, 30 to 50% of glycerol were needed to get average lengths of myosin rods comparable to published values and to the values of freeze-dried molecules (145-149 nm). Below 10% glycerol the average length of rods was shorter by about 10 and 20 nm in intact myosin and isolated rods, respectively. Chloride caused a significant concentration-dependent shortening of myosin rods due to destabilization of the alpha-helical double coiled rod structure. Similar or higher concentrations of volatile salts, not containing chloride as an anion, had no shortening effect. Thus, subtle influences depending on the composition of the dispersion solution on the final appearance and lengths of myosin rods have to be considered, before studying temperature- and pH-dependent changes of myosin rod structure [15].
D000818:Animals; D002645:Chickens; D005990:Glycerol / Q000494:pharmacology*; D066298:In Vitro Techniques; D008854:Microscopy, Electron; D009218:Myosins; D010369:Pectoralis Muscles
D009218:Myosins; D005990:Glycerol