- An experimental and computational investigation into the gas-phase acidities of tyrosine and phenylalanine: Three structures for deprotonated tyrosine
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Using mass spectrometry and correlated molecular orbital theory, three deprotonated structures were revealed for the amino acid tyrosine. The structures were distinguished experimentally by ion/molecule reactions involving proton transfer and trimethylsilyl azide. Gas-phase acidities from proton transfer reactions and from G3(MP2) calculations generally agree well. The lowest energy structure, which was only observed experimentally using electrospray ionization from aprotic solvents, is deprotonated at the carboxylic acid group and is predicted to be highly folded. A second unfolded carboxylate structure is several kcal/mol higher in energy and primarily forms from protic solvents. Protic solvents also yield a structure deprotonated at the phenolic side chain, which experiments find to be intermediate in energy to the two carboxylate forms. G3(MP2) calculations indicate that the three structures differ in energy by only 2.5 kcal/mol, yet they are readily distinguished experimentally. Structural abundance ratios are dependent upon experimental conditions, including the solvent and accumulation time of ions in a hexapole. Under some conditions, carboxylate ions may convert to phenolate ions. For phenylalanine, which lacks a phenolic group, only one deprotonated structure was observed experimentally when electrosprayed from protic solvent. This agrees with G3(MP2) calculations that find the folded and unfolded carboxylate forms to differ by 0.3 kcal/mol. (Chemical Presented).
- Bokatzian, Samantha S.,Stover, Michele L.,Plummer, Chelsea E.,Dixon, David A.,Cassady, Carolyn J.
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- De-novo designed library of benzoylureas as inhibitors of BCL-X L: Synthesis, structural and biochemical characterization
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The prosurvival BCL-2 proteins are attractive yet challenging targets for medicinal chemists. Their involvement in the initiation and progression of many, if not all, tumors makes them prime targets for developing new anticancer therapies. We present our approach based on de novo structure-based drug design. Using known structural information from complexes engaging opposing members of the BCL-2 family of proteins, we designed peptidomimetic compounds using a benzoylurea scaffold to reproduce key interactions between these proteins. A library stemming from the initial de novo designed scaffold led to the discovery of ligands with low micromolar potency (KD = 4 μM) and selectivity for BCL-XL. These compounds bind in the canonical BH3 binding groove in a binding mode distinct from previously known BCL-2 inhibitors. The results of our study provide insight into the design of a new class of antagonists targeting a challenging class of protein-protein interactions.
- Brady, Ryan M.,Vom, Amelia,Roy, Michael J.,Toovey, Nathan,Smith, Brian J.,Moss, Rebecca M.,Hatzis, Effie,Huang, David C. S.,Parisot, John P.,Yang, Hong,Street, Ian P.,Colman, Peter M.,Czabotar, Peter E.,Baell, Jonathan B.,Lessene, Guillaume
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p. 1323 - 1343
(2014/03/21)
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- Alpha-helical mimetics
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Benzoyl urea derivatives that are alpha helical peptides mimetics that mimic BH3-only proteins, compositions containing them, their conjugation to cell-targeting-moieties, and their use in the regulation of cell death are disclosed. The benzoyl urea derivatives are capable of binding to and neutralizing pro-survival Bcl-2 proteins. Use of benzoyl urea derivatives in the treatment and/or prophylaxis of diseases or conditions associated with deregulation of cell death are also described.
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Page/Page column 72
(2011/05/18)
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- ALPHA-HELICAL MIMETICS
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Benzoyl urea derivatives that are alpha helical peptide mimetics that mimic BH3-only proteins, compositions containing them, their conjugation to cell-targeting moieties, and their use in the regulation of cell death are disclosed. The benzoyl urea derivatives are capable of binding to and neutralising pro-survival Bcl-2 proteins. Use of the benzoyl urea derivatives in the treatment and/or prophylaxis of diseases or conditions associated with deregulation of cell death are also disclosed.
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Page/Page column 138-139
(2010/02/15)
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- TRIMETHYLSILYL CYANIDE IN PEPTIDE STRATEGIES. PART III. NEEDLESSNESS FOR COMPLEMENTARY HYDROXYL SIDE-CHAIN PROTECTION
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No extra side-chain protection is needed for Ser, Thr, Tyr, and Cys (nor for Asp and Glu) in peptide syntheses that are mediated by TMS-CN, whereby silylesters and ethers are formed and are stable enough even during activation of carboxylic components.Thi
- Anteunis, M.J.O.,Becu, Chr.,Becu, F.
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p. 133 - 136
(2007/10/02)
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