DAMMIF, an enhanced and significantly faster implementation of the ab-initio shape-determination program DAMMIN for small-angle scattering data, is presented.

New methods for the quantitative evaluation of averaged dummy atom models resulting from small-angle X-ray scattering ab initio shape retrieval programs such as DAMMIN are presented. The techniques are validated for model systems with distinct shapes and size distributions, enabling the use of bead-modelling software for inorganic nanocrystals.

This paper discusses the execution of numerous simultaneous runs of the programs DAMMIN and GASBOR using Condor, which distributes them over a network of PCs; this has allowed a substantial acceleration of the processing of results. The application of Condor to determine the molecular shape of tissue transglut­aminase is presented, thus demonstrating the efficiency of the approach.

A method is described for reconstructing the shapes of protein molecules from X-ray solution scattering data, which involves the progressive confinement of a set of interacting volume-defining points to fit the expected protein volume. Tests with synthetic and experimental data demonstrate that the final distributions of points obtained using this approach correctly map out the protein envelope.

SAXS-based ab initio modelling of the capsids of isometric bacteriophages allows the solution structure of the constituent hollow spheres to be reconstructed reliably. For the shape of their free nucleic acid, however, other advanced modelling approaches are to be preferred.

The X-ray crystallographic structure of RdfS reveals molecular superhelical polymers in the crystal.

An updated template reporting table based on the 2017 publication guidelines for biomolecular SAS and 3D modelling is presented that includes standard descriptions for proteins, glycosylated proteins, DNA and RNA, and some reorganization of the data to improve readability and interpretation. A specialized template has also been developed for reporting SAS contrast-variation data and models that incorporates the additional reporting requirements for these more complicated experiments.

Rsm22-family proteins are conserved putative SAM-dependent methyltransferases with important functions in mitochondrial translation. Here, the results of a comparative bioinformatics analysis of Rsm22-type proteins are presented, the expression, biophysical characterization and crystallization of Saccharomyces cerevisiae Rsm22 are reported, a low-resolution SAXS structure of the protein is revealed, and SAM-dependent RNA methyl transferase activity of the protein is demonstrated.

A method utilizing a spherical harmonics representation of the scattering amplitudes for a rapid superposition of three-dimensional models is developed.

This article discusses the improvement of the ab initio restoration of biomacromolecular structure from small-angle X-ray scattering data, by consideration of an additional type of `dummy atom', representing the hydration layer. The described algorithm has been implemented in the program DENFERT.