scholarly journals The Behavior of NH3+ Torsional Vibration in Amino Acids: A Raman Spectroscopic Study

Crystals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 517
Author(s):  
André Luís de Oliveira Cavaignac ◽  
Ricardo Jorge Cruz Lima ◽  
Paulo Tarso Cavalcante Freire
Keyword(s):  
Crystal Structure ◽  
Amino Acids ◽  
Hydrogen Bonds ◽  
Geometric Parameters ◽  
Positive Slope ◽  
Raman Spectroscopic ◽  
Raman Spectroscopic Study ◽  
Arginine Hydrochloride ◽  
Temperature Lattice ◽  
The Stability

In this work we present the continuation of studies carried out on the changes of geometric parameters of the hydrogen bonds in amino acid crystals subjected to temperature or pressure variations. Changes in geometric parameters of the hydrogen bonds are correlated with the temperature behavior of the Raman wavenumber of NH3+ torsional band. Now four monocrystals, L-valine, L-isoleucine, taurine, and L-arginine hydrochloride monohydrate, are studied. Temperature evolution of the Raman wavenumber of NH3+ torsional band, with positive slope (dν/dT = 0.023 cm−1/K) of L-isoleucine, can be related to the stability of the crystal structure and the hydrogen bonds strengths on heating due to different temperature lattice parameters variation.

scholarly journals Hydrogen Bonds: Raman Spectroscopic Study

2021 ◽  
Vol 22 (10) ◽  
pp. 5380
Author(s):  
Boris A. Kolesov
Keyword(s):  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Spectroscopic Study ◽  
Raman Spectra ◽  
Temperature Region ◽  
Vibrational Frequency ◽  
Chemical Compounds ◽  
Raman Spectroscopic ◽  
Raman Spectroscopic Study ◽  
Proton Dynamics

The work outlines general ideas on how the frequency and the intensity of proton vibrations of X–H×××Y hydrogen bonding are formed as the bond evolves from weak to maximally strong bonding. For this purpose, the Raman spectra of different chemical compounds with moderate, strong, and extremely strong hydrogen bonds were obtained in the temperature region of 5 K–300 K. The dependence of the proton vibrational frequency is schematically presented as a function of the rigidity of O-H×××O bonding. The problems of proton dynamics on tautomeric O–H···O bonds are considered. A brief description of the N–H···O and C–H···Y hydrogen bonds is given.

Raman Spectroscopic Study of Ba2+-Surfactant Interactions in Aqueous Monodisperse Alkylpolyoxyethylene Surfactant Solutions

1993 ◽  
Vol 47 (11) ◽  
pp. 1784-1787
Author(s):  
Diana C. W. Siew ◽  
Ralph P. Cooney ◽  
Michael J. Taylor
Keyword(s):  
Conformational Changes ◽  
Influencing Factor ◽  
Difference Spectroscopy ◽  
Raman Spectroscopic ◽  
Chain Component ◽  
Raman Spectroscopic Study ◽  
Surfactant Solutions ◽  
Surfactant Complex ◽  
Surfactant Interactions ◽  
The Stability

Aqueous monodisperse alkylpolyoxyethylene surfactant-Ba2+ systems were investigated to clarify the coordination effects between the polyether chain and the cation which have been previously identified in polydisperse alkylphenoxy- and alkypolyoxyethylene surfactant systems. The coordination effects are simplified in the present study due to the presence of only a single polyether chain component. Formation of the surfactant complex resulted in conformational changes of the polyether chain which were monitored by Raman difference spectroscopy and curve fitting. The present studies confirm that surfactant-complex formation is dependent upon the polyether chain adopting the TGT-TĜT conformation and that the stability of the complex increases with the number of filled chain sites. The length of the polyether chain is also an influencing factor.

scholarly journals Poly[(μ3-3,5-dinitrobenzoato-κ3O1:O1′:O3)(μ2-hydroxido-κ2O:O)copper(II)]

2014 ◽  
Vol 70 (3) ◽  
pp. m112-m113 ◽  
Author(s):  
B. Sinha ◽  
G. C. Dey ◽  
B. Sarkar ◽  
A. Roy ◽  
Seik Weng Ng ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Three Dimensional ◽  
Title Complex ◽  
Axial Position ◽  
Coordination Geometry ◽  
Carboxylate Ligands ◽  
The Stability

The title complex, [Cu{μ3-O2CC6H3(NO2)2-3,5}(μ-OH)]n, features zigzag chains in which successive pairs of CuIIatoms are connected by OH bridges and bidentate carboxylate ligands, leading to six-membered Cu(O)(OCO)Cu rings. The zigzag chains are connected into a three-dimensional architecture by Cu—O(nitro) bonds. The coordination geometry of the CuIIatom is square-pyramidal, with the axial position occupied by the nitro O atom, which forms the longer Cu—O bond. Bifurcated hydroxy–nitro O—H...O hydrogen bonds contribute to the stability of the crystal structure.

A Raman spectroscopic study of the complexation of the methylmercury(II) cation by amino acids

1987 ◽  
Vol 65 (3) ◽  
pp. 491-496 ◽  
Author(s):  
Serge Alex ◽  
Rodrigue Savoie
Keyword(s):  
Amino Acids ◽  
Spectroscopic Investigation ◽  
Thiol Group ◽  
Amino Groups ◽  
Raman Spectroscopic ◽  
Raman Spectroscopic Study ◽  
Bending Mode ◽  
Stretching Vibration ◽  
Vibrational Bands ◽  
Cation Coordination

A systematic Raman spectroscopic investigation of the complexation of CH3Hg+ by the standard amino acids is reported. It is shown that the vibrational bands due to the ligand—Hg and Hg—CH3 stretching modes and to the symmetric —CH3 bending mode of the —HgCH3 unit are well suited to characterize the extent of complexation and the sites of attachment of the cation. Coordination, which occurs mostly on sulfur and nitrogen atoms by substitution of a proton on the thiol group of cysteine or on amino groups in general, is best identified by the frequency of the ligand—Hg stretching vibration in the 250–550 cm−1 region of the spectrum.

scholarly journals Crystal structure of HECT domain of UBE3C E3 ligase and its ubiquitination activity

2020 ◽  
Vol 477 (5) ◽  
pp. 905-923 ◽  
Author(s):  
Sunil Singh ◽  
J. Sivaraman
Keyword(s):  
Crystal Structure ◽  
Amino Acids ◽  
Enzymatic Activity ◽  
Cancer Metastasis ◽  
E3 Ligase ◽  
The Other ◽  
Hect Domain ◽  
Loop Region ◽  
The Stability

The HECT family of E3 ubiquitin ligase is divided into three subfamilies: the NEDD4, the HERC, and the ‘other’. Previous studies have mostly targeted members of the NEDD4 subfamily for structural and functional analysis. The UBE3C E3 ligase is a member of the ‘other’ subfamily HECT and influences several crucial cellular processes, including innate immunity, proteasome processivity, and cancer metastasis. Here, we report the crystal structure of the HECT domain of UBE3C (amino acids (aa) 744–1083) with an additional fifty N-terminal amino acids (aa 693–743) at 2.7 Å, along with multiple in vitro ubiquitination assays to understand its enzymatic activity. The UBE3C HECT domain forms an open, L-shaped, bilobed conformation, having a large N-lobe and a small C-lobe. We show that the N-terminal region (aa 693–743) preceding the UBE3C HECT domain as well as a loop region (aa 758–762) in the N-lobe of the HECT domain affect the stability and activity of UBE3C HECT domain. Moreover, we identified Lys903 in the UBE3C HECT domain as a major site of autoubiquitination. The deletion of the last three amino acids at the C-terminal completely abrogated UBE3C activity while mutations of Gln961 and Ser1049 residues in the HECT domain substantially decreased its autoubiquitination activity. We demonstrate that these region/residues are involved in the E2–E3 transthiolation process and affect the UBE3C mediated autoubiquitination. Collectively, our study identified key residues crucial for UBE3C enzymatic activity, and it may assist in the development of suitable inhibitors to regulate its activity in multiple cancers.

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