600736-30-9Relevant articles and documents
An unnatural tripeptide structure containing intramolecular double H-bonds mimics a turn hairpin conformation
Gong, Bing,Li, Xiao-Qi,Liu, Jin-Yu,Liu, Rui,Lu, Zhong-Lin,Song, Jun-Jie,Sun, Xue-Yi,Tang, Quan
, p. 4359 - 4363 (2021/05/31)
A series of unnatural tripeptides, each consisting of two aromatic γ-amino acid residues and an ?-amino acid residue, are designed to probe their folding into hairpin conformations. The ?-amino acid residues, with aliphatic or aromatic spacers of different sizes, serve as the loop of the hairpins. Studies based on one-dimensional (1D) 1H NMR performed at different concentrations, solvent polarity, and temperature, along with 2D-NMR studies, demonstrated that the doubly H-bonded aromatic γ-amino acid residues play important roles in driving these tripeptides into the hairpin conformation. The loop based on 5-aminovaleric acid, which offers a four-carbon (CH2)4 spacer, enhanced the stability of the corresponding hairpin, while loops having a shorter, a longer and a more rigid spacer disfavored the formation of the hairpins. Results from computational studies are in good agreement with the experimental observations. Furthermore, the crystal structure of peptide 1b revealed the expected hairpin conformation in the solid state. This turn motif, which contains H-bonded aromatic γ-amino acid residues as the core unit and an ?-amino acid residue serving as the loop, provides a new platform that can be used to obtain a variety of turn conformations by incorporating diverse amino acids into the loops.
Sequence-specific association in aqueous media by integrating hydrogen bonding and dynamic covalent interactions
Li, Minfeng,Yamato, Kazuhiro,Ferguson, Joseph S.,Gong, Bing
, p. 12628 - 12629 (2008/02/05)
Oligoamide strands that associate in a sequence-specific fashion into hydrogen-bonded duplexes in nonpolar solvents were converted into disulfide cross-linked duplexes in aqueous media. Thus, by incorporating trityl-protected thiol groups, which allows the reversible formation of disulfide bonds, into the oligoamide strands, only duplexes consisting of complementary hydrogen-bonding sequences were formed in aqueous solution as well as in methanol. The sequence-specific cross-linking of oligoamide strands was confirmed by MALDI-TOF, reverse-phase HPLC, and by isolating a cross-linked duplex. This study demonstrates that the sequence-specificity characteristic of multiply hydrogen-bonded systems can be extended into competitive media through the interplay of H-bonding and reversible covalent interactions, based on which a new class of molecular associating and ligating units that are compatible with both polar and nonpolar environments can be conveniently obtained. Copyright
