Contribution of structural biology to clinically validated target proteins.

We identified six groups of diseases expected to cause serious future health issues on the basis of a WHO report. Approved drugs for these diseases were associated with 409 target proteins; however, the percentage of selected proteins with full-length structural information deposited in the Protein Data Bank (PDB) was only 9.8%. The reason for the low percentage may be as a result of a disproportionate number of intractable proteins with multiple transmembrane regions and variable, or undefined glycosylation patterns, which impede protein preparation and crystallization, in such druggable proteins. We stress the importance of structural analysis of proteins, especially approved-drug target proteins, and the development of new methods to enable structural analyses of presently intractable proteins. In addition, we present an overview of large structural biology projects.

Effect of mergers and acquisitions on drug discovery: perspective from a case study of a Japanese pharmaceutical company.

The pharmaceutical industry has experienced intermittent waves of mergers and acquisitions (M&As) since the 1980s and recently appeared to be in yet another wave. Previous studies indicated rather negative impacts of consolidation on research and development, suggesting that they do not necessarily lead to long-term reinforcement of research capabilities, although they may enrich the drug pipeline in the short term. However, recent studies have implied a positive side in terms of knowledge-base transfer. Further micro-organizational studies suggested that scientists learned new knowledge and approaches from partner scientists and improved their performance and innovation. These findings imply that measures for the scientist-level integration after M&As would reinforce fundamental research capabilities in the long term.

Chemistry and biology of khafrefungin. Large-scale synthesis, design, and structure-activity relationship of khafrefungin, an antifungal agent.

Large-scale synthesis, design, and structure-activity relationships of khafrefungin are reported. Khafrefungin is an antifungal agent that inhibits inositol phosphorylceramide (IPC) synthase, an enzyme involved in fungal sphingolipid biosynthesis. Unlike other inhibitors that inhibit the corresponding enzyme in fungi and mammals to the same extent, khafrefungin does not impair sphingolipid synthesis in mammals. We have developed an efficient method for large-scale synthesis of khafrefungin, and various khafrefungin derivatives were synthesized based on this method. While most of the khafrefungin derivatives lost antifungal activity, a lactone-type derivative had almost the same activity as khafrefungin. We also designed and synthesized derivatives which contain a five- or six-membered ring at the central part of the structure based on NOE experiments of khafrefungin. A macrocyclic khafrefungin derivative was also synthesized, but the antifungal activity was lost. These results suggest that the structure of khafrefungin might be strictly recognized in fungi.