Ausió J, Subirana J A
Biochemistry. 1982 Nov 9;21(23):5910-8. doi: 10.1021/bi00266a028.
We study several highly charged protamines and some related proteins from the sperm of molluscs. Circular dichroism and hydrodynamic parameters obtained from the sedimentation constant and intrinsic viscosity show that these proteins behave as random coils. However, it appears that a small amount of structure is present at basic pH. The molecular weight of these proteins is determined by several methods. When sedimentation equilibrium is used, we have found that the influence of concentration is much smaller than expected. We have also found that the highly charged nature of these proteins can be properly taken into account by using the methodology presently available [Williams, J. W., Van Holde, K. E., Baldwin, R.L., & Fujita, H. (1958) Chem. Rev. 58, 715; Eisenberg, H. (1976) Biological Macromolecules and Polyelectrolytes in Solution, Oxford University Press, London]. The calculations have been carried out in most cases by the method of Chernyak & Margretova [Chernyak, V. Ya., & Margretova, N.N. (1975) Biochem. Biophys. Res. Commun. 65, 990], which does not require the knowledge of the protein concentration. The overall adequacy of this approach has been ascertained by using as standards histone H1 and the protamine thynnine, both of known molecular weight and different charge densities. An electrophoretic method for the rapid estimation of the molecular weights of this type of proteins is also given. The values obtained by this method, as well as those found either with the Scheraga-Mandelkern equation or from the sedimentation and diffusion constants, agree within experimental error with the values obtained from sedimentation equilibrium.
我们研究了几种来自软体动物精子的高电荷鱼精蛋白及一些相关蛋白质。通过沉降常数和特性粘度获得的圆二色性和流体动力学参数表明，这些蛋白质表现为无规卷曲。然而，在碱性pH条件下似乎存在少量结构。这些蛋白质的分子量通过多种方法测定。当使用沉降平衡法时，我们发现浓度的影响比预期小得多。我们还发现，利用现有方法[威廉姆斯，J.W.，范霍尔德，K.E.，鲍德温，R.L.，&藤田，H.（1958年）《化学评论》58卷，715页；艾森伯格，H.（1976年）《溶液中的生物大分子和聚电解质》，牛津大学出版社，伦敦]能够恰当地考虑这些蛋白质的高电荷性质。大多数情况下，计算是通过切尔尼亚克和马尔格雷托娃的方法[切尔尼亚克，V.Ya.，&马尔格雷托娃，N.N.（1975年）《生物化学与生物物理研究通讯》65卷，990页]进行的，该方法不需要知道蛋白质浓度。通过使用已知分子量和不同电荷密度的组蛋白H1和鲔精蛋白作为标准物，确定了这种方法的整体适用性。还给出了一种快速估算这类蛋白质分子量的电泳方法。通过该方法获得的值，以及用谢拉加 - 曼德尔克恩方程或从沉降和扩散常数得到的值，在实验误差范围内与沉降平衡法得到的值一致。
