García de la Torre J, Harding S E, Carrasco B
Departamento de Química Física, Universidad de Murcia, Spain.
Eur Biophys J. 1999;28(2):119-32. doi: 10.1007/s002490050191.
The hydrodynamic properties of macromolecules and bioparticles, represented by bead models, can be calculated using methods implemented in the computer routine HYDRO. Recently, a new computer routine, SOLPRO, has been presented for the calculation of various SOLution PROperties. These include (1) time-dependent electro-optic and spectroscopic properties related to rotational diffusion, (2) non-dynamic properties like scattering curves, and (3) dimensionless quantities that combine two or more solution properties in a form which depends on the shape of the macromolecule but not on its size. In the present work we describe the inclusion of more of those types of properties in a new version of SOLPRO. Particularly, we describe the calculation of relaxation rates in nuclear magnetic resonance (NMR). For dipolar coupling, given the direction of the dipole the program calculates values of the spectral density, from which the NMR relaxation times can be obtained. We also consider scattering-related properties, namely the distribution of distances for the bead model, which is directly related to the angular dependence of scattered intensity, and the particle's longest distance. We have devised and programmed a procedure to calculate the covolume of the bead model, related to the second virial coefficient and, in general, to the concentration dependence of solution properties. Various shape-dependent dimensionless quantities involving the covolume are calculated. In this paper we also discuss some aspects, namely bead overlapping and hydration, that are not explicitly included in SOLPRO, but should be considered by the user.
由珠模型表示的大分子和生物颗粒的流体动力学性质，可以使用计算机程序HYDRO中实现的方法来计算。最近，提出了一种新的计算机程序SOLPRO，用于计算各种溶液性质。这些性质包括：（1）与旋转扩散相关的随时间变化的电光和光谱性质；（2）像散射曲线这样的非动态性质；（3）以取决于大分子形状而非其大小的形式组合两种或更多种溶液性质的无量纲量。在本工作中，我们描述了在新版本的SOLPRO中纳入更多此类性质。特别地，我们描述了核磁共振（NMR）中弛豫率的计算。对于偶极耦合，给定偶极方向，该程序计算光谱密度值，由此可获得NMR弛豫时间。我们还考虑了与散射相关的性质，即珠模型的距离分布，它与散射强度的角度依赖性直接相关，以及颗粒的最长距离。我们设计并编写了一个程序来计算珠模型的共体积，它与第二维里系数相关，并且一般与溶液性质的浓度依赖性相关。计算了涉及共体积的各种形状相关的无量纲量。在本文中，我们还讨论了一些未明确包含在SOLPRO中但用户应考虑的方面，即珠重叠和水合作用。
