Department of Chemistry, Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pune-, 411 008, India.
Angew Chem Int Ed Engl. 2018 Jan 22;57(4):1057-1061. doi: 10.1002/anie.201711124. Epub 2017 Dec 27.
Double helices are not common in polypeptides and proteins except in the peptide antibiotic gramicidin A and analogous l,d-peptides. In contrast to natural polypeptides, remarkable β-double-helical structures from achiral γ-peptides built from α,β-unsaturated γ-amino acids have been observed. The crystal structures suggest that they adopted parallel β-double helical structures and these structures are stabilized by the interstrand backbone amide H-bonds. Furthermore, both NMR spectroscopy and fluorescence studies support the existence of double-helical conformations in solution. Although a variety of folded architectures featuring distinct H-bonds have been discovered from the β- and γ-peptide foldamers, this is the first report to show that achiral γ-peptides can spontaneously intertwine into β-double helical structures.
除了在肽抗生素短杆菌肽 A 和类似的 l,d-肽中，双螺旋结构在多肽和蛋白质中并不常见。与天然多肽相反，人们已经观察到由α，β-不饱和γ-氨基酸构建的非手性γ-肽产生了显著的β-双螺旋结构。晶体结构表明它们采用了平行的β-双螺旋结构，这些结构通过链间主链酰胺氢键稳定。此外，NMR 光谱和荧光研究都支持在溶液中存在双螺旋构象。尽管已经从β-和γ-肽类构象体中发现了多种具有不同氢键的折叠结构，但这是第一个表明非手性γ-肽可以自发缠绕成β-双螺旋结构的报道。
