Design and Construction of an Open Multistranded β-Sheet Polypeptide Stabilized by a Disulfide Bridge

• Published in: Journal of the American Chemical Society 2002-05, Vol.124 (18), p.4987-4994
• Main Authors: Venkatraman, Janani, Nagana Gowda, Gowda A, Balaram, Padmanabhan
• Format: Article
• Language: English
• Subjects: Amino Acid Motifs; Amino Acid Sequence; Aminoacids, peptides. Hormones. Neuropeptides; Analytical, structural and metabolic biochemistry; Biological and medical sciences; Circular Dichroism; Deuterium; Disulfides - chemical synthesis; Disulfides - chemistry; Fundamental and applied biological sciences. Psychology; Methanol - chemistry; Molecular Sequence Data; Nuclear Magnetic Resonance, Biomolecular; Peptides - chemical synthesis; Peptides - chemistry; Protein Conformation; Protein Structure, Secondary; Proteins; Spectrometry, Fluorescence; Water - chemistry
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja0174276

The design and characterization of an open eight-stranded β-sheet in a synthetic, 2-fold symmetric 70-residue peptide is described. The design strategy involves the generation of a 35-residue four-stranded β-sheet peptide in which successive hairpins are nucleated by appropriately positioned DPro−Xxx sequences. Oxidative dimerization using a single Cys residue positioned at the center of the C-terminal strand results in a disulfide-bridged eight-stranded structure. Nuclear Overhauser effects firmly establish an eight-stranded β-sheet in methanol. In water, the outer strands are frayed, but a well-defined four-stranded β-sheet stabilized by a disulfide bridge and a hydrophobic cluster is determined from NMR data. Comparison of the precursor peptide with the disulfide-bridged dimer reveals considerable enhancement of β-sheet content in the latter, suggesting that the disulfide cross-link is an effective strategy for the stabilization of β-sheets.