Improved hydrodynamic interaction in macromolecular bead models

The calculation of hydrodynamic properties of macromolecules in terms of be ad models requires an adequate description of the hydrodynamic interaction between the spherical elements. For this purpose, the original or modified Oseen tensor are customarily used, although it has been shown that this sim ple description may lead to erroneous results, particularly for rotational coefficients. In this paper we study several more elaborate theories for mu ltisphere systems. We apply those treatments to our problem of rigid bead m odels, implementing them in computer programs, and making calculations for various test structures. The comparison of the results from the various the ories, and from other, presumably very accurate procedures, allow us to giv e some guidelines to improve the treatment of hydrodynamic interactions in macromolecular bead models. These advances are introduced in new versions o f our public-domain computer software. (C) 1999 American Institute of Physi cs. [S0021-9606(99)52234-4].