51504-84-8Relevant academic research and scientific papers
Intra- versus Intermolecular Hydrogen Bonding: Solvent-Dependent Conformational Preferences of a Common Supramolecular Binding Motif from 1H NMR and Vibrational Circular Dichroism Spectra
Demarque, Daniel P.,Merten, Christian
, p. 17915 - 17922 (2017)
When predicting binding properties of small molecules or larger supramolecular aggregates, intra- and intermolecular hydrogen bonds are often considered the most important factor. Spectroscopic techniques such as 1H NMR spectroscopy are typically utilized to characterize such binding events, but interpretation is often qualitative and follows chemical intuition. In this study, we compare the effects of intramolecular hydrogen bonding and solvation on two chiral 2,6-pyridinediyl-dialkylamides. In comparison with 1H NMR spectroscopy, vibrational circular dichroism (VCD) spectroscopy proved to be more sensitive to conformational changes. In fact, the change of the solvent from CDCl3 to [D6]DMSO generates mirror-image VCD spectra for the same enantiomer. Here, the common sense that the sterically less hindered group is more prone to solvation proved to be wrong according predicted VCD spectra, which clearly show that both asymmetric amide hydrogens are equally likely to be solvated, but never simultaneously. The competition between intra- and intermolecular hydrogen bonding and their importance for a correct prediction of spectral properties are discussed.
Affinity adsorption mechanism studies of adsorbents C1-Zn(II) for uremic middle molecular peptides containing Asp-Phe-Leu-Ala-Glu sequence
Li, Pinglin,Fu, Lixue,Qiao, Yitao,Zhao, Jianxin,Wang, Wei,Yuan, Zhi
, p. 375 - 379 (2012/02/03)
To exploit efficient adsorbents for removing middle molecular peptides containing DFLAE (DE5, a typical peptide sequence accumulated in uremic serum) sequence by hemoperfusion, we designed and synthesized three affinity adsorbents (C1-Zn2+, C2-Zn2+ and C3-Zn2+) that could have high affinity to DE5. Subsequently, we evaluated the corresponding adsorption ability of each adsorbent by static adsorption experiments and isothermal titration calorimetry (ITC). The results showed that C1-Zn2+ had the best adsorption ability to DE5-containing peptides and the adsorption capacity for DE5 was 8.52 mg/g. By changing the adsorption conditions, the adsorption mechanism was elucidated. The main driving force of the adsorption is metal-carboxyl coordination and the hydrophobic force affords the cooperative effect. It is expected that our present work can provide basic understanding for the design of adsorbents with high affinity and selectivity towards oligopeptides.
Adsorbents with high selectivity for uremic middle molecular peptides containing the Asp-Phe-Leu-Ala-Glu sequence
Qiao, Yitao,Zhao, Jianxin,Li, Pinglin,Wang, Jun,Feng, Jing,Wang, Wei,Sun, Hongwei,Ma, Yi,Yuan, Zhi
experimental part, p. 7181 - 7187 (2010/12/25)
Asp-Phe-Leu-Ala-Glu (DE5) is a frequent sequence of many toxic middle molecular peptides that accumulate in uremic patients. To eliminate these peptides by hemoperfusion, three adsorbents (CP1-Zn2+, CP2-Zn 2+, and CP3-Zn2+) were designed on the basis of coordination and hydrophobic interactions. Adsorption experiments indicated that CP2-Zn2+ had the highest affinity for DE5 among these three adsorbents. Also, the adsorption capacity of CP2-Zn2+ in DE5 and DE5-containing peptides was about 2-6 times higher than that of peptides without the DE5 sequence. Linear polymers bearing the same functional groups of the adsorbents were used as models to study the adsorption mechanism via isothermal titration calorimetry (ITC) and computer-aided analyses. The results indicated that coordination and hydrophobic interactions played the most important roles in their affinity. When two carboxyl moieties on Asp and Glu residues coordinated to CP2-Zn2+, the hydrophobic interaction took place by the aggregation of the hydrophobic amino acid residues with phenyl group on CP2-Zn2+. The optimal collaboration of these interactions led to the tight binding and selective adsorption of DE5-containing peptides onto CP2-Zn2+. These results may provide new insight into the design of affinity adsorbents for peptides containing DE5-like sequences.
