Hydrogen Bonding of β-Turn Structure Is Stabilized in D<sub>2</sub>O

Cho, Younhee; Sagle, Laura; Iimura, S.; Zhang, Yanjie; Kherb, Jaibir; Chilkoti, Ashutosh; Scholtz, J. Martin; Cremer, Paul S.

doi:10.1021/ja9040785

Cited by 88 publications

(94 citation statements)

References 62 publications

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“…Taken together CD and FTIR analyses confirm that for our hydrophobic oligomers rich in glycine, hydrogen bonding rather than hydrophobicity is the key factor in the stabilization of the collapsed state, as reported in literature for specific ELP-subfamilies. 52,53 On the whole, this work demonstrates that the secondary/tertiary structures are not altered by differing rates of water evaporation and that the aggregation, based on inter-chains recognition, is mainly induced by bridging H-bonds of the polar peptides and altered by hydrophobic hydration and side chains mobility, as specifically shown by the substitution of Val with Leu at the first position of the studied sequences.…”

Section: Discussionmentioning

confidence: 58%

Influence of amino acid specificities on the molecular and supramolecular organization of glycine‐rich elastin‐like polypeptides in water

et al. 2011

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Elastin-like polypeptides adopt complex supramolecular structures, showing either a hydrophobic or a hydrophilic surface, depending on their surrounding environment and the supporting substrate. The preferred organization is important in many situations ranging from biocompatibility to bio-function. Here we compare the n-repeat pentamer LeuGlyGlyValGly (n = 7) with the analogue ValGlyGlyValGly (n = 5), as water suspensions and as deposits on silicon substrates. These sequences contain the repeat XxxGlyGlyZzzGly (Xxx, Zzz = Val, Leu) motif belonging to the hydrophobic glycine-rich domain of elastin and represent a simplified model from which to obtain information on molecular interactions functional to elastin itself. The compounds studied differ only by the presence of the -CH(2)- spacer in the Leu moiety and thus the work was aimed at revealing the influence of this spacer element on self assembly. Both polypeptides were studied under identical conditions, using combined techniques, to identify differences in their conformational states both at molecular (CD, FTIR) and supramolecular (XPS, AFM) levels. By these means, together with a Congo Red spectroscopic assay of β-sheet formation in water, a clear correlation between amino acid sequences (sequence specificity) and their kinetics and ordering of aggregation has emerged. The novel outcomes of this work are from the supplementary measurements, made to augment the AFM and XPS studies, showing that the significant step in the self assembly of both polypeptides takes place in the liquid phase and from the finding that the substitution of Val by Leu in the first position of the pentapeptide effectively inhibits the formation of amyloidal fibers.

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Section: Discussionmentioning

confidence: 58%

Influence of amino acid specificities on the molecular and supramolecular organization of glycine‐rich elastin‐like polypeptides in water

et al. 2011

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“…87,88 By monitoring the time-dependent surface reaction occurring on the photoelectrodes in the presence of water isotopes, the diffuse-reflectance infrared Fourier transform (DRIFT, Fig. 5) technique showed that the intensity of the SCN À ligand remarkably decreased when the water content in the electrolyte (LiI 0.50 M, I 2 50 mM and TBP 0.50 M in ACN; TBP = 4-tert-butylpyridine) increased (from 0 to 5 wt%).…”

Section: Spectroscopic Investigation Of Water-promoted Effectsmentioning

confidence: 99%

Aqueous dye-sensitized solar cells

et al. 2015

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Nowadays, dye-sensitized solar cells (DSSCs) are the most extensively investigated systems for the conversion of solar energy into electricity, particularly for implementation in devices where low cost and good performance are required. Nevertheless, a key aspect is still to be addressed, being considered strongly harmful for a long time, which is the presence of water in the cell, either in the electrolyte or at the electrode/electrolyte interface. Here comes the present review, in the course of which we try our best to address the highly topical role of water in DSSCs, trying to figure out if it is a poisoner or the keyword to success, by means of a thoroughly detailed analysis of all the established phenomena in an aqueous environment. Actually, in the last few years the scientific community has suddenly turned its efforts in the direction of using water as a solvent, as demonstrated by the amount of research articles being published in the literature. Indeed, by means of DSSCs fabricated with water-based electrolytes, reduced costs, non-flammability, reduced volatility and improved environmental compatibility could be easily achieved. As a result, an increasing number of novel electrodes, dyes and electrolyte components are continuously proposed, being highly challenging from the materials science viewpoint and with the golden thread of producing truly water-based DSSCs. If the initial purpose of DSSCs was the construction of an artificial photosynthetic system able to convert solar light into electricity, the use of water as the key component may represent a great step forward towards their widespread diffusion in the market.

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“…Similar phenomena were also observed in other thermosensitive polymers. 58 It is noted that the cloud point of PM-2 is 9.9 C lower in D 2 O than in H 2 O, much less pronounced than the cloud point difference (13.3 C) of PH-2. This suggests that the enhanced steric hindrance suppresses the solvent isotopic effect.…”

Section: -55mentioning

confidence: 81%

Steric hindrance effect on thermo-responsive behaviors of well-defined water-soluble semi-rigid polymers

Liu

Tan

Xiang

et al. 2013

J. Polym. Sci. Part A: Polym. Chem.

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Three series of water-soluble semi-rigid thermo-responsive polymers with well-defined molecular weights based on mesogen-jacketed liquid crystal polymers, poly [bis(N-(2-hydroxypropyl) pyrrolidoneand poly[bis(N-hydroxypropyl pyrrolidone) 2-vinylterephthalate] (PHPPVTA) have been synthesized via reversible addition-fragmentation chain transfer polymerization. The steric hindrance effects on liquid crystalline property and thermo-responsive behaviors of semi-rigid water-soluble polymers (P(2-HPPVTA), P(1-M-2-HEPVTA), and PHPPVTA) were carefully investigated. From molecular structure, the steric hindrance of P(1-M-2-HEPVTA) is stronger than that of P(2-HPPVTA). Polarized light microscope and onedimensional wide-angle X-ray diffraction revealed that both the P(2-HPPVTA) and P(1-M-2-HEPVTA) display a columnar nematic phase, indicating that the steric hindrance effect do not affect liquid crystalline behavior of the polymers. The dynamic light scattering results demonstrated that P(1-M-2-HEPVTA) exhibited lower cloud point compared with that of P(2-HPPVTA) at the same mass concentration and the same molecular weight. The more significant molecular weight and concentration dependence on cloud point have been observed in P(2-HPPVTA) solution than in P(1-M-2-HEPVTA) solution. We also discovered that the cloud points of both P(2-HPPVTA) and P(1-M-2-HEPVTA) solution are lower in D 2 O than in H 2 O. It is noted that the cloud point of PM-2 is 9.9 C lower in D 2 O than in H 2 O, much less pronounced than the cloud point difference of PH-2. The differences of thermo-responsive behaviors between P(2-HPPVTA) and P(1-M-2-HEPVTA) were resulted from the steric hindrance effect existed in their side groups.

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Hydrogen Bonding of β-Turn Structure Is Stabilized in D₂O

Cited by 88 publications

References 62 publications

Influence of amino acid specificities on the molecular and supramolecular organization of glycine‐rich elastin‐like polypeptides in water

Influence of amino acid specificities on the molecular and supramolecular organization of glycine‐rich elastin‐like polypeptides in water

Aqueous dye-sensitized solar cells

Steric hindrance effect on thermo-responsive behaviors of well-defined water-soluble semi-rigid polymers

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Hydrogen Bonding of β-Turn Structure Is Stabilized in D2O

Cited by 88 publications

References 62 publications

Influence of amino acid specificities on the molecular and supramolecular organization of glycine‐rich elastin‐like polypeptides in water

Influence of amino acid specificities on the molecular and supramolecular organization of glycine‐rich elastin‐like polypeptides in water

Aqueous dye-sensitized solar cells

Steric hindrance effect on thermo-responsive behaviors of well-defined water-soluble semi-rigid polymers

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Product

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Hydrogen Bonding of β-Turn Structure Is Stabilized in D₂O