Intermolecular Hydrogen Bonds Formed Between Amino Acid Molecules in Aqueous Solution Investigated by Temperature-jump Nanosecond Time-resolved Transient Mid-IR Spectroscopy

2007 ◽  
Vol 20 (4) ◽  
pp. 461-467 ◽  
Author(s):  
Man-ping Ye ◽  
Heng Li ◽  
Qing-li Zhang ◽  
Yu-xiang Weng ◽  
Xiang-gang Qiu
Keyword(s):  
Aqueous Solution ◽  
Amino Acid ◽  
Ir Spectroscopy ◽  
Hydrogen Bonds ◽  
Temperature Jump ◽  
Intermolecular Hydrogen Bonds ◽  
Time Resolved

scholarly journals Interaction between Negatively Charged Fish Gelatin and Cyclodextrin in Aqueous Solution: Characteristics and Formation Mechanism

Gels ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 260
Author(s):  
Qi Fang ◽  
Nao Ma ◽  
Keying Ding ◽  
Shengnan Zhan ◽  
Qiaoming Lou ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Particle Size ◽  
Secondary Structure ◽  
Hydrogen Bonds ◽  
Gel Strength ◽  
Random Coil ◽  
Fish Gelatin ◽  
Intermolecular Hydrogen Bonds ◽  
Hydrophobic Residues ◽  
Conformation Transitions

The effect that ratios of fish gelatin (FG) to α/β/γ cyclodextrins (α, β, γCDs) had on the phase behavior of a concentrated biopolymer mixture were comparatively investigated. This showed that the formed biopolymer mixture had the highest gel strength at ratios of FG–CD = 90:10. FG could interact with CDs to form stable soluble complexes with lower values of turbidity, particle size and ζ-potential. All of the FG–CD mixture solutions exhibited pseudo-plastic behaviors, and FG–αCD samples had the highest viscosity values than others. The addition of CDs could unfold FG molecules and make conformation transitions of FG from a random coil to β-turn, leading to the environmental change of hydrophobic residues and presenting higher fluorescence intensity, especially for βCDs. FTIR results revealed that the formation of intermolecular hydrogen bonds between FG and CD could change the secondary structure of FG. These findings might help further apply FG–CD complexes in designing new food matrixes.

scholarly journals Metallkomplexe mit Guanidinderivaten als Liganden: Kristallstrukturen von [Zn(cnge)2(SCN)2] · 2H2O und Zn(eoge)Br2 (enge = Cyanoguanidin; eoge = 1-Ethoxyiminomethylguanidin) / Metal Complexes with Guanidine Derivatives as Ligands: Crystal Structures of [Zn(cnge)2(SCN)2]·2H2O und Zn(eoge)Br2 (cnge = Cyanoguanidine; eoge = 1-Ethoxyim inom ethylguanidine)

1996 ◽  
Vol 51 (10) ◽  
pp. 1469-1472 ◽  
Author(s):  
Joachim Pickardt ◽  
Britta Kühn
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Bonds ◽  
Metal Complexes ◽  
Crystal Structures ◽  
Water Molecules ◽  
Monoclinic Space Group ◽  
Intermolecular Hydrogen Bonds ◽  
Crystal Water ◽  
Space Group ◽  
Guanidine Derivatives

Crystals of |Zn(cnge)2(SCN)2]-2H2O (1) were obtained by evaporation of an aqueous solution of Z n(SO4)·7H2O , KSCN, and cyanoguanidine. Crystals of Zn(eoge)Br2 (2) were obtained by reaction of ZnBr2 and cyanoguanidine in ethanol/water. Both compounds are monoclinic, space group C2/c, 1: Z = 4, a = 1919.6(7), b = 467.3(2), c = 1838.5(6) pm, β = 112.99(3)°, 2: Z = 8, a = 1799.5(6), b = 878.7(2), c = 1367.2(5) pm, β = 101.52(3)°. In 1 each Zn is bonded to two cyanoguanidine molecules and via the N atoms to two NCS groups. Intermolecular hydrogen bonds lead to chains along the a-axis, and these chains are again connected via hydrogen bonds to the two crystal water molecules. In the course of the formation of 2, the cyanoguanidine reacted with the ethanol to form 1-ethoxyiminomethylguanidine. This ligand forms chelate rings with the Zn atoms, which are tetrahedrally coordinated by the two imino N atoms of the ligand and by two bromine atoms.

scholarly journals Composite materials based on dental acrylic plastic and chitosan

2021 ◽  
Vol 8 (4) ◽  
pp. 20218413
Author(s):  
L. A. Yakovishin ◽  
E. V. Tkachenko
Keyword(s):  
Composite Materials ◽  
Ir Spectroscopy ◽  
Hydrogen Bonds ◽  
Polymer Composites ◽  
Hydrophobic Interactions ◽  
Mechanochemical Method ◽  
Intermolecular Hydrogen Bonds ◽  
Dental Acrylic ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

Chitosan and poly(methyl methacrylate) (PMMA) composites were synthesized by polymerization with heating and mechanochemical method. The obtained polymer composites were analyzed by the ATR FT-IR spectroscopy method. The presence of intermolecular hydrogen bonds and hydrophobic interactions in formation of PMMA and chitosan polymer composites was shown.

scholarly journals Amyloid-Like Structures Formed by Azobenzene Peptides: Light-Triggered Disassembly

2012 ◽  
Vol 27 ◽  
pp. 387-391 ◽  
Author(s):  
Andreas A. Deeg ◽  
Tobias E. Schrader ◽  
Halina Strzalka ◽  
Jose Pfizer ◽  
Luis Moroder ◽  
...  
Keyword(s):  
Amino Acid ◽  
Ir Spectroscopy ◽  
Time Scale ◽  
Optical Excitation ◽  
Excess Energy ◽  
Structural Rearrangements ◽  
Time Resolved ◽  
Spectral Signatures ◽  
Disassembly Process ◽  
Azobenzene Chromophore

The light-driven disassembly process of amyloid-like structures formed by azobenzene model peptides is studied by time-resolved mid-IR spectroscopy from nanoseconds to minutes. The investigated peptide consists of two amino acid strands connected by the azobenzene switch. The peptides aggregate to amyloid-like structures when the azobenzene chromophore is in thetrans-conformation. Illumination, resulting in atrans-tocis-isomerization of the azobenzene, leads to disaggregation of the aggregated structures. After optical excitation and isomerization of the azobenzene, one finds absorption changes which recover to a large extent on the time scale of few nanoseconds. These early absorption transients are assigned to the relaxation of vibrational excess energy (heat) or to structural rearrangements of isomerized azobenzene and the aggregated surroundings. It is only on the time scale of minutes that spectral signatures appear which are characteristic for the disassembly of the aggregated structure.

Evaluation of Electrospun Poly (Vinyl Alcohol) (PVA)/Gelatin Nanofiber Membrane and Biocompatibility

2010 ◽  
Vol 97-101 ◽  
pp. 2249-2252 ◽  
Author(s):  
Chao Chiung Huang ◽  
Chao Tsang Lu ◽  
Chieh Yu Chao ◽  
Tina Cu Huang ◽  
Ching Wen Lou ◽  
...  
Keyword(s):  
Ir Spectroscopy ◽  
Hydrogen Bonds ◽  
Electric Field ◽  
Ir Spectra ◽  
Vinyl Alcohol ◽  
Volume Ratio ◽  
Poly Vinyl Alcohol ◽  
Electrospun Nanofiber ◽  
Nanofiber Membrane ◽  
Intermolecular Hydrogen Bonds

PVA and gelatin mixed in various volume ratios (100:0, 90:20, 80:20, 70:30, 60:40, 50:50, to 0:100). The effects of the volume ratio on the spinnability of PVA/gelatin solutions were evaluated. The effect on the electrospun nanofiber of PVA/gelatin was examined by IR spectroscopy. Experimental results have demonstrated that solutions of PVA/gelatin in a volume ratio of 80/20 had good spinnability. As the electric field increased, the numbers of beads and droplet decreased. IR spectra demonstrated strong intermolecular hydrogen bonds between the molecules of gelatin and PVA. In this investigation, the best electric field for electrospinning was 0.68 kV/cm. The critical electric field for electrospinning is 0.5 kV/cm.

X-ray studies on crystalline complexes involving amino acids and peptides. XLI. Commonalities in aggregation and conformation revealed by the crystal structures of the pimelic acid complexes of L-arginine and DL-lysine

2003 ◽  
Vol 59 (5) ◽  
pp. 641-646 ◽  
Author(s):  
N. T. Saraswathi ◽  
Siddhartha Roy ◽  
M. Vijayan
Keyword(s):  
Amino Acid ◽  
Hydrogen Bonds ◽  
Molecular Ions ◽  
Pimelic Acid ◽  
Acetate Monohydrate ◽  
Intermolecular Hydrogen Bonds ◽  
X Ray ◽  
Carboxylate Groups ◽  
Aggregation Pattern ◽  
Positively Charged

The complexes of L-arginine and DL-lysine with pimelic acid are made up of singly positively charged zwitterionic amino acid cations and doubly negatively charged pimelate ions in a 2:1 ratio. In both structures, the amino acid molecules form twofold symmetric or centrosymmetric pairs that are stabilized by hydrogen bonds involving α-amino and α-carboxylate groups. In the L-arginine complex, these pairs form columns along the shortest cell dimension, stabilized by intermolecular hydrogen bonds involving α-amino and α-carboxylate groups. The columns are connected by hydrogen bonds and water bridges to give rise to an amino acid layer. Adjacent layers are then connected by pimelate ions. Unlike molecular ions aggregate into alternating distinct layers in the DL-lysine complex. In the amino acid layer, hydrogen-bonded lysinium dimers related by a glide plane are connected by hydrogen bonds involving α-amino and α-carboxylate groups into head-to-tail sequences. Interestingly, the aggregation pattern observed in L-arginine hemipimelate monohydrate is very similar to those in DL-arginine formate dihydrate, DL-arginine acetate monohydrate and L-arginine hemiglutarate monohydrate. Similarly, the aggregation of amino acid molecules is very similar in DL-lysine hemipimelate 0.53-hydrate, DL-lysine formate and DL-lysine hydrochloride. The complexes thus demonstrate how, in related structures, the effects of a change in composition, and sometimes even those of reversal in chirality, can be accommodated by minor adjustments in essentially the same aggregation pattern. It also transpires that the conformation of the argininium ion is the same in the four argininium complexes; the same is true about the conformation of the lysinium ion in the three lysinium complexes. This result indicates a relation between, and mutual dependence of, conformation and aggregation.

Sign in / Sign up

Export Citation Format

Share Document