SELECTIPROBE · Development of selective antagonists and subtype selective ligands for the D-myo-inositol 1,4,5-trisphosphate receptors.""

Development of selective antagonists and subtype selective ligands for the D-myo-inositol 1,4,5-trisphosphate receptors.

Synthesis and development of small molecule probes for the intracellular Ca2+-releasing D-myo-inositol 1,4,5-trisphosphate receptors (InsP3Rs) During these two years the following results have been achieved, according to the planning proposed: - Synthesis of thiazolidinones, TZD and IZD derivatives as phosphate bioisosteres fragments for identifying binding interactions with the HGSA protein. - Identification of binding effects with the HGSA protein by the STD NMR technique. Most of the thiazolidinone amides compounds presented an inhibition activity towards this protein, showing the first non-phosphorus small inhibitors of the HGSA protein. - This project has demonstrated that an approach to screening proteins by STD NMR using a fragment library based on phosphate bioisosteres can rapidly produce evidence of binding and may be of use in finding suitable ligands for other phosphate binding sites. - The solubility problem of synthesized compounds in aqueous media has prevented us from making measurements of the dissociation constant Kd by NMR experiments. However, it was possible to get them by ITC method. We showed that the Kd of our compounds are much higher than the inositol-1,3-biphosphate (InsP2). - We managed to have the crystal structure of three thiazolidinone compounds in the presence of the HGSA protein. The validation of these crystals remains to be confirmed, but can be very useful for docking studies. We have already used this information to our modeling experiments in order to make a selection of potential good inhibitors of this protein and will be useful for the continuity of the project. Future work Working on this project has been very exciting and frustrating at the same time. This project still has plenty to develop, but time is short and we must pass the role to someone else who I'm sure will bring the project further. The first priority will be to validate the STD NMR hits from some of the fragments by using alternative assays. This will not only provide a secondary determination of binding, but may allow for a quantitative estimation of affinity. The crystal structures had been obtained, even with the doubt of their validation, we were able to make docking studies and select a group of molecules that can be good inhibitors for HGSA protein. Their synthesis and tests will be carried out. It would be interesting to see the effects that these modifications would have on binding interactions. During these two years, from the preliminary results we obtained and which were satisfactory and encouraging for the rest of the project, two Part II students (one each year) developed two new series of compounds with other phosphate bioisosteres than the ones developed in this report. Future work of this project will be to continue to develop new structures using the docking experiments, to combine our three results obtained with compounds contained different phosphates bioisosteres and try to get out and have the most effective inhibitor of the HGSA protein.

Data: CORDIS, © European Union