Fricke Holger, Funk Andreas, Schrader Thomas, Gerhards Markus
Heinrich-Heine Universität Düsseldorf, Institut für Physikalische Chemie I, Universitätsstrasse 26.33.O2, 40225 Düsseldorf, Germany.
J Am Chem Soc. 2008 Apr 9;130(14):4692-8. doi: 10.1021/ja076031c. Epub 2008 Mar 18.
An isolated beta-sheet model system is investigated in a molecular beam experiment by means of mass- and isomer-selective IR/R2PI double resonance spectroscopy as well as ab initio and DFT calculations. As the exclusive intermolecular assembly, a beta-sheet motif is formed by spontaneous dimerization of two isolated peptide molecules. This secondary structure is produced from the tripeptide model Ac-Val-Tyr(Me)-NHMe without any further environment to form the binding motif which is analyzed by both the characteristic amide A and I vibrations. The experimental and theoretical investigations yield the assignment to an antiparallel beta-sheet model. The result of this detailed spectroscopic analysis on an isolated beta-sheet model indicates that there are intrinsic properties of a beta-sheet structure which can be formed without a solvent or a peptidic environment.
在分子束实验中，通过质量和异构体选择性红外/里德堡双光子电离（IR/R2PI）双共振光谱以及从头算和密度泛函理论（DFT）计算，对一个孤立的β-折叠模型系统进行了研究。作为唯一的分子间组装形式，β-折叠基序由两个孤立的肽分子自发二聚化形成。这种二级结构由三肽模型Ac-Val-Tyr(Me)-NHMe产生，无需任何其他环境即可形成结合基序，通过特征酰胺A和I振动对其进行分析。实验和理论研究得出该结构为反平行β-折叠模型。对孤立β-折叠模型进行的这种详细光谱分析结果表明，β-折叠结构具有内在特性，无需溶剂或肽环境即可形成。
