Curry J F, Krause S
Department of Chemistry, Rensselaer Polytechnic Institute, Troy, New York 12180.
Biopolymers. 1991 Dec;31(14):1677-87. doi: 10.1002/bip.360311403.
Rabbit skeletal muscle myosin from the same rabbit was prepared by two different methods, and then purified by either Sephadex or hydroxylapatite chromatography. The resulting myosin samples were analyzed in 2-10 mM sodium pyrophosphate solutions at pH 9 using transient electric birefringence. The birefringence decay signals were fitted using a Fortran program called DISCRETE and two relaxation times, 49.7 +/- 5.6 and 11.2 +/- 2.5 microseconds, were determined. These relaxation times were independent of the method of myosin preparation, the method of myosin purification, the concentration of sodium pyrophosphate between 2 and 10 mM, the concentration of myosin between 0.08 and 1.59 mg/mL, and the temperature between 4.0 and 20.0 degrees C, after correction to 20.0 degrees C. The longer relaxation time is consistent with a rigid, linear myosin molecule. The shorter relaxation time is consistent with myosin that has a completely flexible hinge region in the myosin tail. Both relaxation times are inconsistent with the previously reported single relaxation time of myosin obtained by fitting the birefringence decay data to only 90% of the decay signal. By forcing some of the birefringence decay data in the presence work to fit 90% of the decay signal with a single relaxation time, approximately the same relaxation time as previously reported was obtained.
采用两种不同方法制备同一只兔子的兔骨骼肌肌球蛋白，然后通过葡聚糖凝胶或羟基磷灰石色谱法进行纯化。使用瞬态电双折射在pH 9的2 - 10 mM焦磷酸钠溶液中分析所得的肌球蛋白样品。使用名为DISCRETE的Fortran程序拟合双折射衰减信号，确定了49.7±5.6和11.2±2.5微秒这两个弛豫时间。在校正至20.0℃后，这些弛豫时间与肌球蛋白的制备方法、肌球蛋白的纯化方法、2至10 mM之间的焦磷酸钠浓度、0.08至1.59 mg/mL之间的肌球蛋白浓度以及4.0至20.0℃之间的温度无关。较长的弛豫时间与刚性的线性肌球蛋白分子一致。较短的弛豫时间与肌球蛋白尾部具有完全灵活铰链区的肌球蛋白一致。这两个弛豫时间与之前报道的通过将双折射衰减数据拟合到仅90%的衰减信号而获得的肌球蛋白单一弛豫时间不一致。通过在存在功的情况下迫使一些双折射衰减数据用单一弛豫时间拟合90%的衰减信号，获得了与之前报道大致相同的弛豫时间。
