Exploitation of Luminescent Transition Metal Perfluoroarene Complexes as Novel Biological Probes for Peptide Tags and Their Applications in Site-Specific Bioconjugation, Live-Cell Imaging, and Photoinduced Inactivation of Proteins

Project: Research

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The aim of this project is the utilization of luminescent transition metal perfluoroarene complexes as novel probes for the cysteine residue of the -clamp sequence (Phe-Cys-Pro-Phe), leading to the development of innovative reagents for site-specific bioconjugation, live-cell imaging, and photoinduced inactivation of proteins. Specific labeling of proteins in live cells is an important but challenging task. Although the development of fluorescent proteins (FPs) has made a substantial contribution to studies of the expression, trafficking, and interaction of proteins, their applications have been limited by their relatively large molecular size, difficulty in modifying the chromophores, and low photostability. A more recent approach is the fusion of the protein of interest to a genetically encoded artificial peptide, which serves as a tag to direct the subsequent bioconjugation with a chemical probe. This method exhibits the specificity of protein labeling with FPs, but only requires a short recognition sequence and is compatible with robust fluorescent probes. In recent years, the remarkable emission properties and cytotoxic activity of luminescent transition metal complexes have facilitated the design of versatile bioimaging reagents and potent anticancer drugs. Although many luminescent metal complexes have revealed organelle-targeting properties, it is still impossible to specifically label a natural amino acid in a genetically encoded peptide or protein sequence for bioimaging and protein functional studies. Hence, the favorable properties of luminescent metal complexes, which include their intense and long-lived emission and controllable cytotoxic activity, cannot be fully exploited. Following the recent discovery of the -clamp sequence (Phe-Cys-Pro-Phe), which allows highly specific cysteine modification by perfluoroarene derivatives, we envisage that luminescent transition metal complexes with an unprecedented capability for bioconjugation can be developed. In this project, we will design new luminescent transition metal perfluoroarene complexes as specific probes for the cysteine residue of the -clamp sequence. The photophysical and photochemical properties of the complexes and their bioconjugation reactivity toward peptides and proteins fused to the -clamp sequence will be examined. Additionally, the cellular uptake, cytotoxicity, and bioimaging properties of the complexes, and their applications in chromophore-assisted light inactivation (CALI) of proteins in aqueous buffer and in live cells will be investigated. We are confident that the integration of the favorable characteristics of luminescent transition metal complexes and intriguing peptide-recognition capability will afford novel reagents for site-specific bioconjugation, bioimaging, and photoinduced inactivation of proteins.


Project number9042534
Grant typeGRF
Effective start/end date1/09/17 → …