Rosser R W, Schrag J L, Ferry J D, Greaser M
Macromolecules. 1977 Sep-Oct;10(5):978-80. doi: 10.1021/ma60059a018.
The storage and loss shear moduli, G' and G'', have been measured for dilute solutions of paramyosin from the clam Mercenaria mercenaria in water and glycerol--water mixtures containing potassium chloride and phosphate buffer. The Birnboim--Schrag multiple-lumped resonator was used in the frequency range from 150 to 8100 Hz; the concentration range was 0.7 to 2 X 10(-3) g/mL and the temperature range was 0.0 to 6.0 degrees C. The intrinsic moduli were obtained by extrapolation to infinite dilution. When compared with predictions of Yamakawa for a rigid cylindrical molecule, they agreed at low frequencies but diverged at high frequencies. Excellent agreement was obtained with calculations for a hybrid model whose relaxation times are attributed to rigid-body end-over-end rotation together with some internal modes of motion, probably flexural. The rotational relaxation time agreed rather well with that determined by DeLaney and Krause from electrical birefringence measurements. From the ratio of the rotational to the longest flexural relaxation time, the flexural rigidity and Young's modulus of the paramyosin molecule were estimated by relations derived by Wada and collaborators; the modulus was 1.2 X 10(10) dyn/cm2.
已经对来自硬壳蛤的副肌球蛋白在水以及含有氯化钾和磷酸盐缓冲液的甘油 - 水混合物中的稀溶液测量了储能剪切模量G'和损耗剪切模量G''。在150至8100Hz的频率范围内使用了Birnboim - Schrag多集总谐振器；浓度范围为0.7至2×10⁻³g/mL，温度范围为0.0至6.0℃。通过外推至无限稀释获得本征模量。与山川对刚性圆柱形分子的预测相比，它们在低频时一致，但在高频时出现偏差。对于一个混合模型的计算结果取得了极好的一致性，该模型的弛豫时间归因于刚体的端对端旋转以及一些内部运动模式，可能是弯曲模式。旋转弛豫时间与德莱尼和克劳斯通过电双折射测量确定的结果相当吻合。根据旋转弛豫时间与最长弯曲弛豫时间的比值，利用和田及其合作者推导的关系式估算了副肌球蛋白分子的弯曲刚度和杨氏模量；模量为1.2×10¹⁰dyn/cm²。
