Practical aspects of low-resolution shape determination in small-angle
scattering studies of biological macromolecules in solution are consi
dered. The shape restoration method using spherical harmonics [Svergun
, Volkov, Kozin & Stuhrmann (1996). Acta Cryst. A52, 419-426] is exten
ded to account for deviations from the idealized model and to work dir
ectly on raw experimental data sets. An algorithm to restore the struc
ture of homodimeric particles in terms of the shape of the monomer and
the separation between the monomers is implemented. Applications of t
he program to the shape restoration of several proteins, with known an
d unknown crystal structures, from X-ray solution-scattering data are
presented.