- COUMARIN-BASED CROSSLINKING REAGENTS
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Disclosed herein are novel coumarin-based reagents, e.g. linkers, and conjugates including one or more of the disclosed coumarin-based reagents. In some embodiments, the presence of a coumarin moiety within the coumarin-based reagents enables detection of labels which are typically difficult to detect, e.g. certain haptens.
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Paragraph 0348; 0349
(2020/04/25)
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- Synthetic Fluorogenic Peptides Reveal Dynamic Substrate Specificity of Depalmitoylases
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Palmitoylation is a post-translational modification involving the thioesterification of cysteine residues with a 16-carbon-saturated fatty acid. Little is known about rates of depalmitoylation or the parameters that dictate these rates. Here we report a modular strategy to synthesize quenched fluorogenic substrates for the specific detection of depalmitoylase activity and for mapping the substrate specificity of individual depalmitoylases. We demonstrate that human depalmitoylases APT1 and APT2, and TgPPT1 from the parasite Toxoplasma gondii, have distinct specificities that depend on amino acid residues distal to the palmitoyl cysteine. This information informs the design of optimal and non-optimal substrates as well as isoform-selective substrates to detect the activity of a specific depalmitoylase in complex proteomes. In addition to providing tools for studying depalmitoylases, our findings identify a previously unrecognized mechanism for regulating steady-state levels of distinct palmitoylation sites by sequence-dependent control of depalmitoylation rates. Amara et al. describe a method for preparing positional scanning libraries of fluorogenic palmitoylated peptide substrates. This allowed identification of residues that are distal to the palmitoylation site that impact turnover. This information allowed the design of substrates that are selective for a specific depalmitoylating enzyme.
- Amara, Neri,Foe, Ian T.,Onguka, Ouma,Garland, Megan,Bogyo, Matthew
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p. 35 - 7,47
(2018/10/24)
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- Structure-Activity Relationships of Potent, Targeted Covalent Inhibitors That Abolish Both the Transamidation and GTP Binding Activities of Human Tissue Transglutaminase
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Human tissue transglutaminase (hTG2) is a multifunctional enzyme. It is primarily known for its calcium-dependent transamidation activity that leads to formation of an isopeptide bond between glutamine and lysine residues found on the surface of proteins, but it is also a GTP binding protein. Overexpression and unregulated hTG2 activity have been associated with numerous human diseases, including cancer stem cell survival and metastatic phenotype. Herein, we present a series of targeted covalent inhibitors (TCIs) based on our previously reported Cbz-Lys scaffold. From this structure-activity relationship (SAR) study, novel irreversible inhibitors were identified that block the transamidation activity of hTG2 and allosterically abolish its GTP binding ability with a high degree of selectivity and efficiency (kinact/KI > 105 M-1 min-1). One optimized inhibitor (VA4) was also shown to inhibit epidermal cancer stem cell invasion with an EC50 of 3.9 μM, representing a significant improvement over our previously reported "hit" NC9.
- Akbar, Abdullah,McNeil, Nicole M. R.,Albert, Marie R.,Ta, Viviane,Adhikary, Gautam,Bourgeois, Karine,Eckert, Richard L.,Keillor, Jeffrey W.
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supporting information
p. 7910 - 7927
(2017/10/06)
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- Synthesis and evaluation of self-calibrating ratiometric viscosity sensors
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We describe the design, synthesis and fluorescent profile of a family of self-calibrating dyes that provide ratiometric measurements of fluid viscosity. The design is based on covalently linking a primary fluorophore (reference) that displays a viscosity-independent fluorescence emission with a secondary fluorophore (sensor) that exhibits a viscosity-sensitive fluorescence emission. Characterization of fluorescent properties was made with separate excitation of the units and through Resonance Energy Transfer from the reference to the sensor dye. The chemical structures of both fluorophores and the linker length have been evaluated in order to optimize the overall brightness and sensitivity of the viscosity measurements. We also present an application of such ratiometric dyes for the detection of membrane viscosity changes in a liposome model.
- Yoon, Hyung-Jo,Dakanali, Marianna,Lichlyter, Darcy,Chang, Willy M.,Nguyen, Karen A.,Nipper, Matthew E.,Haidekker, Mark A.,Theodorakis, Emmanuel A.
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supporting information; experimental part
p. 3530 - 3540
(2011/06/25)
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