Here, we present the algorithm and validation for OMEGA, a systematic, knowledge-based conformer generator. The algorithm consists of three phases: assembly of an initial 3D structure from a library of fragments; exhaustive enumeration of all rotatable torsions using values drawn from a knowledge-based list of angles, thereby generating a large set of conformations; and sampling of this set by geometric and energy criteria. Validation of conformer generators like OMEGA has often been undertaken by comparing computed conformer sets to experimental molecular conformations from crystallography, usually from the Protein Databank (PDB). Such an approach is fraught with difficulty due to the systematic problems with small molecule structures in the PDB. Methods are presented to identify a diverse set of small molecule structures from cocomplexes in the PDB that has maximal reliability. A challenging set of 197 high quality, carefully selected ligand structures from well-solved models was obtained using these methods. This set will provide a sound basis for comparison and validation of conformer generators in the future. Validation results from this set are compared to the results using structures of a set of druglike molecules extracted from the Cambridge Structural Database (CSD). OMEGA is found to perform very well in reproducing the crystallographic conformations from both these data sets using two complementary metrics of success.

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The devaluation of the recorded music commodity under digitalization has destabilized the recording industry. One primary record industry response is the new “360 deal” form of the recording contract. By securing rights to individual acts’ live performance, music publishing and licensing, and merchandizing activities, this new deal expands record companies’ access to more profitable fields of music industry activity (if in piecemeal fashion). We examine the context, evolution, and varieties of the 360 deal, and argue that it re-secures record industry profitability and further stratifies the population of recording artists by shifting risk onto performers.La dévaluation marchande de la musique qui accompagne la numérisation a déstabilisé l’industrie de l’enregistrement sonore en Amérique du nord. Cet article en explore l’une des principales réponses: le nouveau contrat “360 degrés.” En leur assurant des droits sur le spectacle vivant, l’édition musicale et les activités reliées aux produits dérivés d’artistes individuels, ce nouveau contrat élargit l’accès des maisons de disques à des champs d’activité industrielle plus rentables (même de façon fragmentaire). Nous proposons de rendre compte du contexte, de l’évolution et de la diversité des contrats 360 degrés, arguant qu’en reléguant la responsabilité des risques et des investissements aux artistes, l’industrie de l’enregistrement sonore ré-assure sa rentabilité et polarise davantage la population entre artistes établis et de la relève, fortifiant la position des premiers et intensifiant la vulnérabilité des seconds.

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