Fluorescent Amino Acid Undergoing Excited State Intramolecular Proton Transfer for Site-Specific Probing and Imaging of Peptide Interactions

• DOI: 10.1021/jp508748e
• Publication Date: 2014-10-13T13:38:16Z
• Authors: Marianna Sholokh; Oleksandr M. Zamo...; Ranjan Das; Viktoriia Y. Post...; Ludovic Richert; Denis Dujardin; Olga A. Zaporozhets; Vasyl G. Pivovarenko; Andrey S. Klymchenko; Yves Mély
• Keywords: BODIPY

Fluorescent amino acids bearing environment-sensitive fluorophores are highly valuable tools for site-selective probing of peptide/ligand interactions. Herein, we synthesized a fluorescent l-amino acid the 4′-methoxy-3-hydroxyflavone fluorophore (M3HFaa) that shows dual emission, as result an excited state intramolecular proton transfer (ESIPT). The emission M3HFaa was found to be substantially more sensitive hydration compared previous analogues. By replacing Ala30 and Trp37 residues HIV-1 nucleocapsid peptide, observed preserve peptide structure functions. Interaction labeled peptides with nucleic lipid vesicles produced strong switch in their favoring ESIPT product. This associated appearance long-lived fluorescence lifetimes product, consequence rigid environment complexes restricted relative motions aromatic moieties. strongest restriction thus longest were at position 37 acids, where probe likely stacks nucleobases. Based on dependence lifetime values nature ligand position, two-photon imaging used identify binding partners microinjected into living cells. Thus, appears tool monitoring site selectively interactions solution