Structural Insights into Plant Viruses Revealed by Small-Angle X-ray Scattering and Atomic Force Microscopy.

The structural study of plant viruses is of great importance to reduce the damage caused by these agricultural pathogens and to support their biotechnological applications. Nowadays, X-ray crystallography, NMR spectroscopy and cryo-electron microscopy are well accepted methods to obtain the 3D protein structure with the best resolution. However, for large and complex supramolecular structures such as plant viruses, especially flexible filamentous ones, there are a number of technical limitations to resolving their native structure in solution. In addition, they do not allow us to obtain structural information about dynamics and interactions with physiological partners. For these purposes, small-angle X-ray scattering (SAXS) and atomic force microscopy (AFM) are well established. In this review, we have outlined the main principles of these two methods and demonstrated their advantages for structural studies of plant viruses of different shapes with relatively high spatial resolution. In addition, we have demonstrated the ability of AFM to obtain information on the mechanical properties of the virus particles that are inaccessible to other experimental techniques. We believe that these under-appreciated approaches, especially when used in combination, are valuable tools for studying a wide variety of helical plant viruses, many of which cannot be resolved by classical structural methods.

Synthesis and Evaluation of Novel [1,2,4]Triazolo[5,1-c][1,2,4]-triazines and Pyrazolo[5,1-c][1,2,4]triazines as Potential Antidiabetic Agents.

Inhibition of the dipeptidyl peptidase-4 (DPP4) enzyme activity and prevention of advanced glycation end (AGE) products formation represents a reliable approach to achieve control over hyperglycemia and the associated pathogenesis of diabetic vascular complications. In the frames of this research study, several triazolo- and pyrazolotriazines were synthesized and evaluated as inhibitors of AGE products formation, DPP4, glycogen phosphorylase and α-glucosidase activities, as well as AGE cross-link breakers. From the two considered classes of heterocyclic compounds, the pyrazolotriazines showed the highest potency as antiglycating agents and DPP4 inhibitors. Structure-activity relationships (SAR) for these compounds, which can be considered as potential drugs for the treatment of type 2 diabetes, were evaluated.