2024-03-29T06:28:56Zhttps://eprints.lib.hokudai.ac.jp/dspace-oai/requestoai:eprints.lib.hokudai.ac.jp:2115/469082022-11-17T02:08:08Zhdl_2115_20055hdl_2115_8527In-crystal affinity ranking of fragment hit compounds reveals a relationship with their inhibitory activitiesYamane, JunjiYao, MinZhou, YongHiramatsu, YasuyukiFujiwara, KenichiroYamaguchi, TohruYamaguchi, HirotoTogame, HirokoTsujishita, HidekiTakemoto, HiroshiTanaka, Isaoopen access499Fragment-based drug discovery (FBDD), which is a molecular build-up strategy from small scaffolds, has recently become a promising approach for lead-compound generation. Although high-throughput protein crystallography is usually used to determine the protein-ligand complex structure and identify potential hit compounds, the relationship between the quality of the Fo-Fc maps of hit compounds and their inhibitory activities has rarely been examined. To address this issue, crystallographic competition experiments were carried out to determine the relative order of the in-crystal binding affinities using five hit compounds of bovine pancreatic trypsin inhibitors. Soaking experiments of all combinations of the five hit compounds were used to define the in-crystal affinity ranking. Based on characterization by a high-concentration bioassay, a clear correlation was observed between in-crystal binding affinities and the inhibitory activities in solution. Moreover, the correlation analysis revealed that X-ray-based screening can detect a weak hit compound with inhibitory activity below the limit of detection, even in a high-concentration assay. The proposed crystallographic competition method could function as a valuable tool, not only to select a plausible starting scaffold for subsequent synthetic efforts but also to access structure-activity relationships using fragment compounds with a wider detection limit than a biological assay. The crystallographic validation methodology described here will greatly accelerate the hit-to-lead process during fragment-based and structure-based drug design.International Union of Crystallography2011-08engjournal articleVoRhttp://hdl.handle.net/2115/46908https://doi.org/10.1107/S00218898110177170021-8898Journal of Applied Crystallography444798804https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/46908/1/JAC44-4_798-804.pdfapplication/pdf636.39 KB2011-08