Jeffrey DeStefano, an HIV researcher at the University of Maryland, College Park and post-doc Gauri Nair published a paper in 2008 about their development of a new inhibitor of HIV RT (reverse transcriptase), the viral enzyme which copies viral RNA into DNA in order that it might be incorporated into the host cell's chromosomes by another viral enzyme, integrase (3). The RT inhibitor consisted of a 38 base pair piece of DNA with a particular sequence which binds tightly to the enzyme.

Students will have a day and a half of lectures and hands-on software tutorials on the basics of BioSAXS data collection and processing from expert practitioners in the field. This will be followed by real data collection on MacCHESS beamlines (F1 and G1 stations).

And, the tiny beam has to hit the tiny crystal. The location of the beam can be well determined and doesn't change, but how do we know where the crystal is?

There are four known families of membrane-immersed proteases (enzymes which break protein chains); all four carry out important functions and damage to them is implicated in pathologies including cancer, Parkinson's disease, impaired resistance to parasites, and more. When a mutation results in overactivity of a membrane protease, an inhibitor of the protease can be effective treatment for a disease. Designing such inhibitors has proven difficult, largely because of incomplete understanding of the catalytic process in the intramembrane environment.

But what if large crystals are not available? A team of scientists at MacCHESS and the University of Toronto is pushing what is possible for small protein crystals at storage ring sources.

BioSAXS Essentials is specifically designed as a short, just-the-essentials course for non-specialists wishing to collect and publish BioSAXS data for the first time.

Usually, HPC has negligible effect on the crystal structure. Occasionally, it causes a small change in packing of the molecules in the crystal. For crystals containing a lot of solvent, pressure may cause them to collapse, destroying their diffraction. HPC on crystals of Snf7, however, results in a large change in molecular packing without destroying the crystallinity. In fact, the pressure-cooled crystals diffract better than the normally cooled crystals, in spite of a 30% decrease in unit cell volume!

While the foundational physics of scattering is common to all application areas, individual fields have diverged over the years to develop many specialized tools appropriate to the type of matter under investigation. As science advances, however, areas like structural biology, materials science, and engineering have greater overlap. We organized a dual-track workshop this year aimed at getting soft-matter scientists and biologists in one room to promote exchange.

In the 1970s, canine parvovirus type 2 (CPV-2) came to the scene, and had spread around the world by 1978 to be almost completely replaced by a mutant CPV-2a variant by the end of the eighties. The CPV-2a variant has a broad host range infecting both domestic and wild carnivores (incl. dogs and cats). It’s been hypothesized that CPV-2a may be displacing FPV-like viruses in many wild carnivore hosts. Understanding the structural basis of virus-host recognition is therefore of utmost importance to be able to design strategies for intercepting infections with this high-fatality rate virus.

At the lowest level, compaction is achieved by wrapping stretches of DNA around a core of histone proteins to form nucleosomes in a “beads on a string” configuration: 147 base pairs of DNA per nucleosome, with linkers of variable length between nucleosomes. The nucleosome core particle (NCP), or one “bead”, consists of 4 types of histone (H2A, H2B, H3, and H4), each of which has a compact core plus a positively-charged, flexible tail that protrudes from the core.