- Single-Site Labeling of Native Proteins Enabled by a Chemoselective and Site-Selective Chemical Technology
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Chemical biology research often requires precise covalent attachment of labels to the native proteins. Such methods are sought after to probe, design, and regulate the properties of proteins. At present, this demand is largely unmet due to the lack of empowering chemical technology. Here, we report a chemical platform that enables site-selective labeling of native proteins. Initially, a reversible intermolecular reaction places the "chemical linchpins" globally on all the accessible Lys residues. These linchpins have the capability to drive site-selective covalent labeling of proteins. The linchpin detaches within physiological conditions and capacitates the late-stage installation of various tags. The chemical platform is modular, and the reagent design regulates the site of modification. The linchpin is a multitasking group and facilitates purification of the labeled protein eliminating the requirement of additional chromatography tag. The methodology allows the labeling of a single protein in a mixture of proteins. The precise modification of an accessible residue in protein ensures that their structure remains unaltered. The enzymatic activity of myoglobin, cytochrome C, aldolase, and lysozyme C remains conserved after labeling. Also, the cellular uptake of modified insulin and its downstream signaling process remain unperturbed. The linchpin directed modification (LDM) provides a convenient route for the conjugation of a fluorophore and drug to a Fab and monoclonal antibody. It delivers trastuzumab-doxorubicin and trastuzumab-emtansine conjugates with selective antiproliferative activity toward Her-2 positive SKBR-3 breast cancer cells.
- Adusumalli, Srinivasa Rao,Rawale, Dattatraya Gautam,Singh, Usha,Tripathi, Prabhanshu,Paul, Rajesh,Kalra, Neetu,Mishra, Ram Kumar,Shukla, Sanjeev,Rai, Vishal
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- Chemoselective and Site-Selective Lysine-Directed Lysine Modification Enables Single-Site Labeling of Native Proteins
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The necessity for precision labeling of proteins emerged during the efforts to understand and regulate their structure and function. It demands selective attachment of tags such as affinity probes, fluorophores, and potent cytotoxins. Here, we report a method that enables single-site labeling of a high-frequency Lys residue in the native proteins. At first, the enabling reagent forms stabilized imines with multiple solvent-accessible Lys residues chemoselectively. These linchpins create the opportunity to regulate the position of a second Lys-selective electrophile connected by a spacer. Consequently, it enables the irreversible single-site labeling of a Lys residue independent of its place in the reactivity order. The user-friendly protocol involves a series of steps to deconvolute and address chemoselectivity, site-selectivity, and modularity. Also, it delivers ordered immobilization and analytically pure probe-tagged proteins. Besides, the methodology provides access to antibody-drug conjugate (ADC), which exhibits highly selective anti-proliferative activity towards HER-2 expressing SKBR-3 breast cancer cells.
- Adusumalli, Srinivasa Rao,Kalra, Neetu,Purushottam, Landa,Rai, Vishal,Rawale, Dattatraya Gautam,Reddy, Neelesh C.,Shukla, Sanjeev,Thakur, Kalyani
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- MULTI-FUNCTIONAL CHEMICAL AGENTS, AND THE METHOD FOR PROTEIN MODIFICATION
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A multifunctional chemical agents comprising functional agents Fn1, Fn2 and linkers, for the linchpin directed (LDM), protein directed (PDPM) modifications of proteins, and Fn1 accelerated kinetic labeling by Fn2.
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- CDK INHIBITORS CONTAINING A ZINC BINDING MOIETY
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The present invention relates to CDK inhibitors and their use in the treatment of cell proliferative diseases such as cancer. The compounds of the invention may further act as HDAC inhibitors.
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(2009/04/25)
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