Kung Vanessa M, Cornilescu Gabriel, Gellman Samuel H
Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, WI 53706 (USA).
National Magnetic Resonance Facility at Madison, University of Wisconsin-Madison, 433 Babcock Dr., Madison, WI 53706 (USA).
Angew Chem Int Ed Engl. 2015 Nov 23;54(48):14336-9. doi: 10.1002/anie.201506448. Epub 2015 Oct 12.
We have examined whether parallel β-sheet secondary structure becomes more stable as the number of β-strands increases, via comparisons among peptides designed to adopt two- or three-stranded parallel β-sheet conformations in aqueous solution. Our three-strand design is the first experimental model of a triple-stranded parallel β-sheet. Analysis of the designed peptides by nuclear magnetic resonance (NMR) and circular dichroism (CD) spectroscopy supports the hypothesis that increasing the number of β-strands, from two to three, increases the stability of the parallel β-sheet. We present the first experimental evidence for cooperativity in the folding of a triple-stranded parallel β-sheet, and we show how minimal model systems may enable experimental documentation of characteristic properties, such as CD spectra, of parallel β-sheets.
我们通过比较设计用于在水溶液中采用两链或三链平行β-折叠构象的肽,研究了随着β-链数量的增加,平行β-折叠二级结构是否变得更稳定。我们的三链设计是三链平行β-折叠的首个实验模型。通过核磁共振(NMR)和圆二色性(CD)光谱对设计的肽进行分析,支持了以下假设:将β-链数量从两条增加到三条会增加平行β-折叠的稳定性。我们提供了三链平行β-折叠折叠过程中协同性的首个实验证据,并且展示了最小模型系统如何能够实现对平行β-折叠特征性质(如CD光谱)的实验记录。