Mathematics and School Biology

A model, based on commercially available beads, is described. The model enables many of the biochemical and chromosomal processes involved in the transmission of the genetic material to be easily and cheaply illustrated.     

PubChem Protein,Gene, Pathway,and Taxonomy Data Collections: Bridging Biology and Chemistry through Target-Centric Views of PubChem Data

PubChem (https://pubchem.ncbi.nlm.nih.gov) is a public chemical database at the U.S. National Institutes of Health. Visited by millions of users every month, it plays a role as a key chemical information resource for biomedical research communities. Data in PubChem is from hundreds of contributors and organized into multiple collections by record type. Among these are the Protein, Gene, Pathway, and Taxonomy data collections. Records in these collections contain information on chemicals related to a given biological target (i.e., protein, gene, pathway, or taxon), helping users to analyze and interpret the biological activity data of molecules. In addition, annotations about the biological targets are collected from authoritative or curated data sources and integrated into the four collections. The content can be programmatically accessed through PubChem’s web service interfaces (including PUG View). A machine-readable representation of this content is also provided within PubChemRDF.     

Molecular Packing in Virus Crystals: Geometry, Chemistry, and Biology

An automated procedure was developed to determine the geometrical and chemical interactions of crystalline virus particles using the crystal parameters, particle position, orientation, and atomic coordinates for an icosahedral asymmetric unit. Two applications of the program are reported: (1) An analysis of a novelpseudo-rhombohedral (R32) symmetry present in the monoclinic crystal lattices of both Nodamura Virus (NOV) and Coxsackie virus B3 (CVB3). The study shows that in both cases the interactions between particles is substantially increased by minor deviations from exact R32 symmetry and that only particles with the proper ratio of dimensions along twofold and fivefold symmetry axes (such as southern bean mosaic virus) can achieve comparable buried surface area in the true R32 space group. (2) An attempt was made to correlate biological function with remarkably conserved interparticle contact regions found in different crystal forms of three members of the nodavirus family, NOV, Flock House Virus (FHV), and Black Beetle Virus (BBV). Mutational evidence implicates the quasi-threefold region on the viral surface in receptor binding in nodaviruses and this region is dominant in particle contacts in all three virus crystals. Examination of particle contacts in numerous crystal structures of viruses in the picornavirus superfamily showed that portions of the capsid surface known to interact with a receptor or serve as an epitope for monoclonal antibodies frequently stabilize crystal contacts.