Fricke H, Schäfer G, Schrader T, Gerhards M
Heinrich-Heine Universität Düsseldorf, Institut für Physikalische Chemie I, Universitätsstrasse 26.33.O2, 40225 Düsseldorf, Germany.
Phys Chem Chem Phys. 2007 Aug 28;9(32):4592-7. doi: 10.1039/b706519a. Epub 2007 Jul 25.
In this paper the structure of the isolated tetrapeptide model Ac-Leu-Val-Tyr(Me)-NHMe (Leu = leucine, Val = valine, Tyr = tyrosine) is investigated by mass- and isomer-selective IR/UV double resonance spectroscopy. Two isomers of this peptide are observed and in combination with force field, ab initio, and DFT calculations these structures are assigned to folded arrangements presenting two different secondary structure binding motifs: (a) a combined gamma-turn/beta-turn structure and (b) a triple gamma-turn structure, which is described for the first time for an isolated model system in the gas phase.
本文通过质量和异构体选择性红外/紫外双共振光谱研究了分离出的四肽模型Ac-Leu-Val-Tyr(Me)-NHMe（Leu = 亮氨酸，Val = 缬氨酸，Tyr = 酪氨酸）的结构。观察到该肽的两种异构体，并结合力场、从头算和密度泛函理论计算，将这些结构归为呈现两种不同二级结构结合基序的折叠排列：(a) 组合的γ-转角/β-转角结构和(b) 三重γ-转角结构，这是首次在气相中针对分离的模型系统描述此类结构。
