title: Design and physicochemical properties of new fluorescent ligands of protein kinase C isozymes focused on CH/pi interaction.
abstract: Phorbol ester-type tumor promoters such as indolactam-V (IL-V, 1) bind to the C1 domains of protein kinase C (PKC) isozymes. A more convenient method to investigate the interaction between each tumor promoter and PKC C1 domain is needed. Focusing on our recent finding that the indole ring of IL-V is involved in the CH/pi interaction with Pro-11 of the PKCdelta-C1B domain, we developed new fluorescent probes (2-4) from IL-V by forming a pyrroloindazole ring. Compound 2 without a substituent at the pyrroloindazole ring bound most strongly to PKC C1 domains with a potency similar to IL-V, but its fluorescent intensity was the weakest of any of the probes. Although the binding affinity of 3 with a methyl group was significantly weaker than that of IL-V, 4 with a trifluoromethyl group showed moderate affinity and the most potent fluorescence intensity. The fluorescence intensity and emission maxima of 4 changed significantly when bound to the PKCdelta-C1B peptide in both the presence and absence of phosphatidylserine. These results suggest that 4 could be a useful probe for analyzing the interaction of tumor promoters with PKC C1 domains.
authors.affiliation: Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Sugimoto
authors.forename: Koji
authors.initials: K
authors.lastname: Itagaki
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Irie
mesh_terms: D001665:Binding Sites; D005456:Fluorescent Dyes / Q000138:chemical synthesis / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology; D007527:Isoenzymes / Q000737:chemistry / Q000378:metabolism; D047029:Lactams, Macrocyclic / Q000138:chemical synthesis / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology; D008024:Ligands; D015394:Molecular Structure; D010703:Phorbol Esters / Q000138:chemical synthesis / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology; D011493:Protein Kinase C / Q000737:chemistry* / Q000378:metabolism*; D013329:Structure-Activity Relationship
chemical_list: D005456:Fluorescent Dyes; D007527:Isoenzymes; D047029:Lactams, Macrocyclic; D008024:Ligands; D010703:Phorbol Esters; D011493:Protein Kinase C