Calsenilin is a member of the recoverin branch of the EF-hand superfamily that is reported to interact with presenilins, regulate prodynorphin gene expression, modulate voltage-gated Kv4 potassium channel function, and bind to neurotoxins. Calsenilin is a Ca+2-binding protein and plays an important role in calcium signaling. Despite its importance in numerous neurological functions, the structure of this protein has not been reported. In the absence of Ca+2, the protein has limited spectral resolution that increases upon the addition of Ca+2. Here, we describe the three-dimensional solution structure of EF-hands 3 and 4 of calsenilin in the Ca+2-bound form. The Ca+2-bound structure consists of five alpha-helices and one two-stranded antiparallel beta-sheet. The long loop that connects EF hands 3 and 4 is highly disordered in solution. In addition to its structural effects, Ca+2 binding also increases the protein's propensity to dimerize. These changes in structure and oligomerization state induced upon Ca+2 binding may play important roles in molecular recognition during calcium signaling.
As part of a fully integrated and comprehensive strategy to discover novel antibacterial agents, NMR‐ and mass spectrometry‐based affinity selection screens were performed to identify compounds that bind to protein targets uniquely found in bacteria and encoded by genes essential for microbial viability. A biphenyl acid lead series emerged from an NMR‐based screen with the Haemophilus influenzae protein HI0065, a member of a family of probable ATP‐binding proteins found exclusively in eubacteria. The structure–activity relationships developed around the NMR‐derived biphenyl acid lead were consistent with on‐target antibacterial activity as the Staphylococcus aureus antibacterial activity of the series correlated extremely well with binding affinity to HI0065, while the correlation of binding affinity with B‐cell cytotoxicity was relatively poor. Although further studies are needed to conclusively establish the mode of action of the biphenyl series, these compounds represent novel leads that can serve as the basis for the development of novel antibacterial agents that appear to work via an unprecedented mechanism of action. Overall, these results support the genomics‐driven hypothesis that targeting bacterial essential gene products that are not present in eukaryotic cells can identify novel antibacterial agents.
Drug discovery has historically advanced by synergy and chance. These are proving insufficient to meet the needs of the marketplace and the demands of modern medicine. We describe our strategic approaches to building and employing flexible informatics tools to transform and improve the workflows and efficiencies of the early-stages of target development in drug discovery. We contrast our approach to strategies that have recently evolved at startup biotechnology companies who use similar technological approaches to drug development but who are less encumbered by precedent and history.