Discovery of novel and potent CRTH2 antagonists.

High throughput screening of our chemical library for CRTH2 antagonists provided a lead compound 1a. Initial optimization of the lead led to the discovery of a novel, potent and orally bioavailable CRTH2 antagonist 17.

Selective ligand purification using high-performance affinity beads.

Since the development of affinity chromatography, affinity purification technology has been applied to many aspects of biological research, becoming an indispensable tool. Efficient strategies for the identification of biologically active compounds based on biochemical specificity have not yet been established, despite widespread interest in identifying chemicals that directly alter biomolecular functions. Here, we report a novel method for purifying chemicals that specifically interact with a target biomolecule using reverse affinity beads, a receptor-immobilized high-performance solid-phase matrix. When FK506-binding protein 12 (FKBP12) immobilized beads were used in this process, FK506 was efficiently purified in one step either from a mixture of chemical compounds or from fermented broth extract. The reverse affinity beads facilitated identification of drug/receptor complex binding proteins by reconstitution of immobilized ligand/receptor complexes on the beads. When FKBP12/FK506 and FKBP12/rapamycin complexes were immobilized, calcineurin and FKBP/rapamycin-associated protein were purified from a crude cell extract, respectively. These data indicate that reverse affinity beads are powerful tools for identification of both specific ligands and proteins that interact with receptor/ligand complexes.

FR225659-binding proteins: identification as serine/threonine protein phosphatase PP1 and PP2A using high-performance affinity beads.

FR225659 was originally isolated as a novel gluconeogenesis inhibitor produced by fungal strain Helicomyces sp. No. 19353. To identify the target protein of FR225659, we synthesized high-performance affinity latex beads that immobilized FR225659 derivative FR253761 or FR259383. Using these beads, we identified FR225659 binding proteins as serine/threonine protein phosphatase type1 (PP1) and type2A (PP2A) from rat hepatocyte crude extract. FR225659 and its synthetic derivatives were strongly inhibited the enzyme activities of purified catalytic subunits of PP1 and PP2A in vitro.

Design and synthesis of a solid-supported FR225659 derivative for its receptor screening.

[structure: see text] We describe the design and synthesis of latex particles attached to an FR225659 derivative to identify its receptor proteins. Two key building blocks were prepared by two-step degradation of FR225659 under basic conditions. The designed ligand showed an acceptable level of biological activity to make it of potential value for use in affinity-supported receptor identification. Affinity purification of FR225659-binding proteins using the latex nanoparticles provided three candidate receptor peptides for the biological activity.

The novel gluconeogenesis inhibitors FR225659 and FR225656 from Helicomyces sp. No. 19353. III. Structure determination.

During the course of screening for novel gluconeogenesis inhibitors, FR225659 and its related compounds were isolated from a fermentation broth of Helicomyces sp. No. 19353. Spectroscopic analysis concluded that FR225659 is an N-acyl tripeptide consisting of a novel acyl, a 3-chloro-4-hydroxyarginine, a 3-hydroxy-3-methylproline and a dehydrovaline. Degradation study allowed assignment of the absolute configuration of the 3-hydroxy-3-methylproline to be (2S,3R). FR225656 was shown to possess a dehydroisoleucine instead of the dehydrovaline of FR225659.