- Isotopically Labeled Desthiobiotin Azide (isoDTB) Tags Enable Global Profiling of the Bacterial Cysteinome
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Rapid development of bacterial resistance has led to an urgent need to find new druggable targets for antibiotics. In this context, residue-specific chemoproteomic approaches enable proteome-wide identification of binding sites for covalent inhibitors. Described here are easily synthesized isotopically labeled desthiobiotin azide (isoDTB) tags that shortened the chemoproteomic workflow and allowed an increased coverage of cysteines in bacterial systems. They were used to quantify 59 % of all cysteines in essential proteins in Staphylococcus aureus and enabled the discovery of 88 cysteines that showed high reactivity, which correlates with functional importance. Furthermore, 268 cysteines that are engaged by covalent ligands were identified. Inhibition of HMG-CoA synthase was verified and will allow addressing the bacterial mevalonate pathway through a new target. Overall, a broad map of the bacterial cysteinome was obtained, which will facilitate the development of antibiotics with novel modes-of-action.
- Zanon, Patrick R. A.,Lewald, Lisa,Hacker, Stephan M.
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- Tunable Methacrylamides for Covalent Ligand Directed Release Chemistry
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Targeted covalent inhibitors are an important class of drugs and chemical probes. However, relatively few electrophiles meet the criteria for successful covalent inhibitor design. Here we describe α-substituted methacrylamides as a new class of electrophiles suitable for targeted covalent inhibitors. While typically α-substitutions inactivate acrylamides, we show that hetero α-substituted methacrylamides have higher thiol reactivity and undergo a conjugated addition-elimination reaction ultimately releasing the substituent. Their reactivity toward thiols is tunable and correlates with the pKa/pKb of the leaving group. In the context of the BTK inhibitor ibrutinib, these electrophiles showed lower intrinsic thiol reactivity than the unsubstituted ibrutinib acrylamide. This translated to comparable potency in protein labeling, in vitro kinase assays, and functional cellular assays, with improved selectivity. The conjugate addition-elimination reaction upon covalent binding to their target cysteine allows functionalizing α-substituted methacrylamides as turn-on probes. To demonstrate this, we prepared covalent ligand directed release (CoLDR) turn-on fluorescent probes for BTK, EGFR, and K-RasG12C. We further demonstrate a BTK CoLDR chemiluminescent probe that enabled a high-throughput screen for BTK inhibitors. Altogether we show that α-substituted methacrylamides represent a new and versatile addition to the toolbox of targeted covalent inhibitor design.
- Reddi, Rambabu N.,Resnick, Efrat,Rogel, Adi,Rao, Boddu Venkateswara,Gabizon, Ronen,Goldenberg, Kim,Gurwicz, Neta,Zaidman, Daniel,Plotnikov, Alexander,Barr, Haim,Shulman, Ziv,London, Nir
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supporting information
p. 4979 - 4992
(2021/05/04)
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- AN ACTIVITY-GUIDE MAP OF ELECTROPHILE-CYSTEINE INTERACTIONS IN PRIMARY HUMAN IMMUNE CELLS
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Disclosed herein are methods, pharmaceutical compositions, and vaccines for modulating an immune response. Also disclosed herein are methods, pharmaceutical compositions, and vaccines for inducing an immune response.
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Paragraph 0250; 0257
(2021/04/23)
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- COMPOSITIONS AND METHODS OF MODULATING IMMUNE RESPONSE
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Disclosed herein are methods, pharmaceutical compositions, and vaccines for modulating an immune response. Also disclosed, herein are methods, pharmaceutical compositions, and vaccines for inducing an immune response.
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Paragraph 0324
(2018/01/17)
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