Title: Generation of new protein kinase inhibitors utilizing cytochrome p450 mutant enzymes for indigoid synthesis.

Authors: Guengerich, F Peter; Sorrells, Jennifer L; Schmitt, Sophie; Krauser, Joel A; Aryal, Pramod; Meijer, Laurent

Published In J Med Chem, (2004 Jun 03)

Abstract: Indigoids, a class of bis-indoles, represent a promising protein kinase inhibitor scaffold. Oxidation of indole by cytochrome P450 (P450) has been shown to generate species (indoxyl, isatin) that couple to yield indigo and indirubin. Escherichia coli-expressed human P450 2A6 mutants isolated from a randomized library were incubated with 27 substituted indole derivatives. Extracts of the cultures were screened for inhibition of human cyclin-dependent kinases (CDK)-1 and -5 and glycogen synthase kinase-3 (GSK3). The extracts from cultures incubated with 5-methoxyindole were the most inhibitory. High-performance liquid chromatography (HPLC) separation yielded a mixture of seven colored indigoids. These indigoids included indigo, indirubin, the di(5-methoxy) derivatives of indigo and indirubin, and both of the possible mono 5-methoxy derivatives of indirubin, which were all identified by visible, mass, and NMR spectra. Cultures with 5-methylindole added to the media also yielded inhibitory material, and 5- and 5'-methylindirubin were characterized. The most inhibitory of these indigoids were the monosubstituted indirubins and 5,5'-dimethoxyindirubin, which was > or =10x more active than indirubin. Thus, the overall approach involves the use of a library of randomized enzyme mutants to activate component moieties of a desired set of larger molecules, thus yielding a library of drug candidates that can be screened and characterized. The general strategy may have additional applications.

PubMed ID: 15163202

MeSH Terms: Aryl Hydrocarbon Hydroxylases/genetics; Aryl Hydrocarbon Hydroxylases/isolation & purification; Aryl Hydrocarbon Hydroxylases/metabolism*; CDC2 Protein Kinase/antagonists & inhibitors; Chromatography, High Pressure Liquid; Cyclin-Dependent Kinase 5; Cyclin-Dependent Kinases/antagonists & inhibitors; Cytochrome P-450 CYP2A6; Escherichia coli/metabolism; Glycogen Synthase Kinase 3/antagonists & inhibitors; Humans; Indoles/chemistry; Indoles/isolation & purification; Indoles/metabolism*; Mixed Function Oxygenases/genetics; Mixed Function Oxygenases/isolation & purification; Mixed Function Oxygenases/metabolism*; Mutation; Protein Kinase Inhibitors*