title: Semisynthesis and optimization of G protein-coupled receptor mimics.
abstract: We have recently developed a soluble mimic of the corticotropin-releasing factor receptor type 1 (CRF1), a membrane-spanning G protein-coupled receptor, which allowed investigations on receptor-ligand interactions. The CRF1 mimic consists of the receptor N-terminus and three synthetic extracellular loops (ECL1-3), which constitute the extracellular receptor domains (ECDs) of CRF1, coupled to a linear peptide template. Here, we report the synthesis of a modified CRF1 mimic, which is more similar to the native receptor possessing a cyclic template that displays the ECDs in a more physiological conformation compared with the initial linear design. In order to facilitate detailed biophysical investigations on CRF1 mimics, we have further established a cost-efficient access to the CRF1 mimic, which is suitable for isotopic labeling for NMR spectroscopy. To this end, the loop-mimicking cyclic peptide of the ECL2 of CRF1 was produced recombinantly and cyclized by expressed protein ligation. Cyclic ECL2 was obtained in milligram scale, and CRF1 mimics synthesized from this material displayed the same binding properties as synthetic CRF1 constructs.
authors.affiliation: Department of Chemical Biology, Leibniz-Institut für Molekulare Pharmakologie (FMP), Robert-Roessle-Str. 10, 13125, Berlin, Germany.
authors.forename: Sabine
authors.initials: S
authors.lastname: Abel
authors.forename: Bernhard
authors.initials: B
authors.lastname: Geltinger
authors.forename: Nadja
authors.initials: N
authors.lastname: Heinrich
authors.forename: Dagmar
authors.initials: D
authors.lastname: Michl
authors.forename: Annerose
authors.initials: A
authors.lastname: Klose
authors.forename: Michael
authors.initials: M
authors.lastname: Beyermann
authors.forename: Dirk
authors.initials: D
authors.lastname: Schwarzer
mesh_terms: D000595:Amino Acid Sequence; D032701:Biomimetics; D008024:Ligands; D018716:Molecular Mimicry; D008969:Molecular Sequence Data; D011487:Protein Conformation; D015202:Protein Engineering; D017434:Protein Structure, Tertiary; D018019:Receptors, Corticotropin-Releasing Hormone / Q000096:biosynthesis* / Q000737:chemistry* / Q000235:genetics; D011994:Recombinant Proteins / Q000138:chemical synthesis / Q000737:chemistry / Q000235:genetics; D000099052:CRF Receptor, Type 1
chemical_list: D008024:Ligands; D018019:Receptors, Corticotropin-Releasing Hormone; D011994:Recombinant Proteins; D000099052:CRF Receptor, Type 1
keywords: G protein-coupled receptor; cyclopeptide synthesis; expressed protein ligation; receptor mimics