排序方式: 共有12条查询结果,搜索用时 15 毫秒
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Vladimir Y. Torbeev Erik Fumi Marc‐Olivier Ebert W. Bernd Schweizer Donald Hilvert 《Helvetica chimica acta》2012,95(12):2411-2420
α‐Methyl‐L ‐proline is an α‐substituted analog of proline that has been previously employed to constrain prolyl peptide bonds in a trans conformation. Here, we revisit the cis‐trans prolyl peptide bond equilibrium in derivatives of α‐methyl‐L ‐proline, such as N‐Boc‐protected α‐methyl‐L ‐proline and the hexapeptide H‐Ala‐Tyr‐αMePro‐Tyr‐Asp‐Val‐OH. In Boc‐α‐methyl‐L ‐proline, we found that both cis and trans conformers were populated, whereas, in the short peptide, only the trans conformer was detected. The energy barrier for the cis‐trans isomerization in Boc‐α‐methyl‐L ‐proline was determined by line‐shape analysis of NMR spectra obtained at different temperatures and found to be 1.24 kcal/mol (at 298 K) higher than the corresponding value for Boc‐L ‐proline. These findings further illuminate the conformationally constraining properties of α‐methyl‐L ‐proline. 相似文献
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Robrecht M. A. Vergauwe Anoop Thomas Kalaivanan Nagarajan Atef Shalabney Jino George Thibault Chervy Marcus Seidel Eloïse Devaux Vladimir Torbeev Thomas W. Ebbesen 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(43):15468-15472
Vibrational strong coupling (VSC) has recently emerged as a completely new tool for influencing chemical reactivity. It harnesses electromagnetic vacuum fluctuations through the creation of hybrid states of light and matter, called polaritonic states, in an optical cavity resonant to a molecular absorption band. Here, we investigate the effect of vibrational strong coupling of water on the enzymatic activity of pepsin, where a water molecule is directly involved in the enzyme's chemical mechanism. We observe an approximately 4.5‐fold decrease of the apparent second‐order rate constant kcat/Km when coupling the water stretching vibration, whereas no effect was detected for the strong coupling of the bending vibration. The possibility of modifying enzymatic activity by coupling water demonstrates the potential of VSC as a new tool to study biochemical reactivity. 相似文献
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Abhishek Baral Aromal Asokan Valentin Bauer Bruno Kieffer Vladimir Torbeev 《Tetrahedron》2019,75(6):703-708
Chemical composition of tumor suppressor protein p53 is altered via multiple post-translational modifications which modulate its cellular lifetime and interactions with other biomolecules. Here we report total chemical synthesis of a 61-residue form of transactivation domain (TAD) of p53 based on native chemical ligation of three peptide segments. The experiments to characterize its binding to nuclear co-activator binding domain (NCBD) of CREB-binding protein confirmed native-like induced folding upon binding to NCBD. Thus, the synthetic approach described herein can be useful for the preparation of various post-translationally modified analogues of TAD-p53 for further functional biochemical and biophysical studies. 相似文献
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