title: Identification of novel peptide agonists from a random peptide library for a 5-oxo-ETE receptor, a receptor for bioactive lipids.
abstract: A combinatorial peptide library contains an enormous combination of amino acid sequences and drug candidates, but an effective screening strategy to identify a variety of bioactive peptides has yet to be established. In this article, a random hexapeptide library was screened to identify novel peptide ligands for a 5-oxo-ETE receptor (OXER), which is a G-protein-coupled receptor for bioactive lipids, by using an OXER-Gi1alpha fusion protein. We successfully identified 2 hexapeptides-Ac-HMQLYF-NH2 and Ac-HMWLYF-NH(2)-that exhibited agonistic activity. Although the corresponding affinities were relatively low (EC50 values of 146 and 6.7 microM, respectively), the activities were confirmed by other independent cell-based assay methods, namely, intracellular calcium mobilization and cell chemotaxis. This study demonstrates that a combinatorial peptide library may be screened using a [35S]GTPgammaS binding assay with G-protein-coupled receptor (GPCR)-Galpha fusion proteins, in general, and that of peptide ligands can be obtained even for nonpeptide receptors.
authors.affiliation: Department of Chemistry and Chemical Biology, Graduate School of Engineering, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Sasaki
authors.forename: Takashi
authors.initials: T
authors.lastname: Tsujii
authors.forename: Shigeki
authors.initials: S
authors.lastname: Takeda
authors.forename: Hideru
authors.initials: H
authors.lastname: Obinata
authors.forename: Takashi
authors.initials: T
authors.lastname: Izumi
authors.forename: Keiichi
authors.initials: K
authors.lastname: Yamada
authors.forename: Ryoichi
authors.initials: R
authors.lastname: Katakai