Nelli Yella Reddy, Antunes Stéphanie, Salaün Arnaud, Thinon Emmanuelle, Massip Stéphane, Kauffmann Brice, Douat Céline, Guichard Gilles
Université de Bordeaux, CNRS, Institut Polytechnique de Bordeaux, UMR 5248 CBMN, Institut Européen de Chimie et Biologie, 2 rue Robert Escarpit, 33607 Pessac (France).
Chemistry. 2015 Feb 9;21(7):2870-80. doi: 10.1002/chem.201405792. Epub 2014 Dec 21.
Nearly isosteric oxo to thioxo substitution was employed to interrogate the structure of foldamers with a urea backbone and explore the relationship between helical folding and hydrogen-bonding interactions. A series of oligomers with urea bonds substituted by thiourea bonds at discrete or all positions in the sequence have been prepared and their folding propensity was studied by using a combination of spectroscopic methods and X-ray diffraction. The outcome of oxo to thioxo replacements on the helical folding was found to depend on whether central or terminal ureas were modified. The canonical helix geometry was not affected upon insertion of thioureas close to the negative end of the helix dipole, whereas thioureas close to the positive pole were found to increase the terminal flexibility and cause helix fraying. Perturbation was amplified when a selenourea was incorporated instead, leading to a structure that is only partly folded.
采用近乎等排的氧代到硫代取代来研究具有脲主链的折叠体结构，并探索螺旋折叠与氢键相互作用之间的关系。已制备了一系列在序列中离散位置或所有位置被硫脲键取代脲键的低聚物，并通过光谱方法和X射线衍射相结合的方式研究了它们的折叠倾向。发现氧代到硫代取代对螺旋折叠的影响取决于修饰的是中央脲还是末端脲。当在靠近螺旋偶极负极的位置插入硫脲时，标准螺旋几何结构不受影响，而靠近正极的硫脲则会增加末端柔韧性并导致螺旋磨损。当掺入硒脲时，这种扰动会放大，导致形成仅部分折叠的结构。
