Selection of fluorescent biosensors against galectin-3 from an NBD-modified phage library displaying designed α-helical peptides.

Affiliation

Hashimoto M(1), Miki T(2), Chang IV(1), Tsutsumi H(1), Mihara H(3).
Author information:
(1)School of Life Science and Technology, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8501, Japan.
(2)School of Life Science and Technology, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8501, Japan. Electronic address: [Email]
(3)School of Life Science and Technology, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8501, Japan. Electronic address: [Email]

Abstract

Fluorescent biosensors are indispensable tools for molecular imaging, detection, and drug screening. Conventionally, fluorescent biosensors were constructed by incorporating fluorophores into ligands. Here, to develop ligand-independent biosensors, we demonstrated biosensor selection from a fluorophore-modified peptide phage library. In this library, the peptides were designed to form α-helical structures, and one cysteine, the probe modification site, was located at the center of four randomized residues on the same face of the helix. By conjugation with 4-nitrobenzoxadiazole (NBD), we constructed an NBD-modified phage library. We conducted selection against galectin-3 (Gal-3), a galactose-specific lectin associated with various biological events such as tumor metastasis and insulin resistance. After biopanning, we obtained NBD-modified peptides that selectively bind to Gal-3 from the library. The fluorescence intensity of the hit biosensors increased with the concentration of Gal-3, and this fluorescent response was visually observed.