A.V. Voronkov, A.A. Glushko

Being a paracrine gland, endothelium regulates vascular tone, processes of blood coagulation, inflammation, proliferation, central neural system metabolism support, filtration function of kidneys, etc. It should be noted that endothelial dysfunction, according to the modern scientific point of view, lies in the basis of many cardio-vascular diseases. Thus, the endothelium is an important target for pharmacotherapy of cardiovascular system, and the search for new substances with endothelial-protective activity is now one of the most important tasks of medicinal chemistry. Many directions of endothelial protective pharmacotherapy exist and most of them are aimed to nitric oxide (NO) production stimulation by NO-synthase regulation. In endothelium cells this enzyme is endothelial NO-synthase (eNOS). Many ways of eNOS activity regulation are known. For example, the regulation of eNOS substrate L-arginine intracellular concentration can help to normalize the intracellular concentration of nitric oxide in the pathological state. Also the eNOS activity regulation can be performed by stimulating or blocking of receptors of endotheliocytes: angiotensin receptors AT1 (AT1a and AT1b), serotonin receptors 5-HT2-A and 5-HT1-B, histamine receptors H1 and H2 and Ca2+ - channels. Another important way of endothelial NO production regulation is the phosphorylation by proteinkinases. Proteinkinases C inhibits the activity of eNOS enzyme by phosphorylating of Thr-495 and by dephosphorylating of Ser-1177. Proteinkinase C molecule consists of regulatory and catalytic domains. The spatial structure of many proteinkinases was determined by the X-ray crystallography. To evaluate the binding affinity of proteinkinase inhibitors to the active site of this enzyme we used the molecular docking with Autodock 4.1 program. As a target for molecular docking the model of proteinkinase-C-η molecule created with the help of the x-ray diffraction data was used. There were used 21 derivatives of isoquinoline andnaphthyridine as ligands with known biological activity. With the help of programs Autodock (The Scripps Research Institute, USA), MGL Tools (The Scripps Research Institute, USA), AutodockMaster (Pyatigorsk Branch of The Volgograd State Medical University, Russia) and AD4Intermol (Pyatigorsk Branch of The Volgograd State Medical University, Russia) molecular docking was performed for training and test sets.Calculations were performed using cluster consisting of 19 computers containing 40 cores totally. AutodockMaster program was used for the distributed calculation management. There were 100 conformations of ligand-receptor complex obtained for every substance. Scoring functions were calculated using AD4Intermol program. Scoring function was used as the mean value of aminoacid-ligand interaction energies absolute values products for every substance in all its conformations. The correlation coefficient of the test set between predicted and experimental values of pIC50 was 0.83 and N = 11. The proposed model is an effective tool for the virtual screening of substances with endothelial-protective activity.