Hydrogen Exchange Study on the Hydroxyl Groups of Serine and Threonine Residues in Proteins and Structure Refinement Using NOE Restraints with Polar Side-Chain Groups

2011 ◽  
Vol 133 (43) ◽  
pp. 17420-17427 ◽  
Author(s):  
Mitsuhiro Takeda ◽  
JunGoo Jee ◽  
Akira M. Ono ◽  
Tsutomu Terauchi ◽  
Masatsune Kainosho
Keyword(s):  
Hydrogen Exchange ◽  
Structure Refinement ◽  
Side Chain ◽  
Hydroxyl Groups ◽  
Exchange Study

A Deuterium-Hydrogen Exchange Study of Inhibitor-Induced Conformational Changes in Ribonuclease A

1971 ◽  
Vol 21 (3) ◽  
pp. 393-399 ◽  
Author(s):  
Genevieve Nonnenmacher ◽  
Eliane Viala ◽  
Jean Marie Thiery ◽  
Paul Calvet
Keyword(s):  
Conformational Changes ◽  
Hydrogen Exchange ◽  
Ribonuclease A ◽  
Exchange Study

Hydrogen-exchange study of lysozyme conformation changes induced by inhibitor binding

Biochemistry ◽  
1974 ◽  
Vol 13 (16) ◽  
pp. 3273-3277 ◽  
Author(s):  
R. R. Wickett ◽  
G. J. Ide ◽  
A. Rosenberg
Keyword(s):  
Hydrogen Exchange ◽  
Inhibitor Binding ◽  
Conformation Changes ◽  
Exchange Study

H-bonding scheme in allactite: a combined single-crystal X-ray and neutron diffraction, optical absorption spectroscopy, FTIR and EPMA-WDS study

2016 ◽  
Vol 80 (5) ◽  
pp. 719-732 ◽  
Author(s):  
G. Diego Gatta ◽  
Ferdinando Bosi ◽  
Maria Teresa Fernandez Diaz ◽  
Ulf Hålenius
Keyword(s):  
Neutron Diffraction ◽  
Optical Absorption ◽  
Single Crystal ◽  
Absorption Spectroscopy ◽  
Structure Refinement ◽  
Site Occupancy ◽  
Optical Absorption Spectroscopy ◽  
Hydroxyl Groups ◽  
X Ray ◽  
Bonding Scheme

AbsatractThe crystal chemistry of allactite from Långban, Värmland (Sweden) was investigated by single-crystal X-ray and neutron diffraction, optical absorption spectroscopy, Fourier-transform infra-red spectroscopy (FTIR) and electron microprobe analysis by wavelength-dispersive spectroscopy (EPMA-WDS). The optical spectra indicate the presence of Mn in valence state 2+ only. Assuming 16 O atoms per formula unit, arsenic as As5+and the (OH) content calculated by charge balance, the resulting formula based on the EPMA-WDS data is (Mn2+6.73Ca0.13Mg0.12Zn0.02)∑7.00(As5+)2.00O16H8, very close to the ideal composition Mn7(AsO4)2(OH)8. In the unpolarized FTIR spectrum of allactite, fundamental (OH)-stretching bands are observed at 3236, 3288, 3387, 3446, 3484, 3562 and 3570 cm–1, suggesting that a number of OH environments, with different hydrogen bond strengths, occur in the structure. The neutron structure refinement shows that four independent H sites occur in allactite with full site occupancy, all as members of hydroxyl groups. The complex hydrogen-bonding scheme in the allactite structure is now well defined, with at least nine hydrogen bonds energetically favourable with mono-, bi- and trifurcated configurations.

Convenient preparation of a β-O-4-type lignin model trimer via KOH-catalyzed hydroxymethylation and a new protection method

Holzforschung ◽  
2013 ◽  
Vol 67 (2) ◽  
pp. 129-136 ◽  
Author(s):  
Maarit Lahtinen ◽  
Anssi Haikarainen ◽  
Jussi Sipilä
Keyword(s):  
Model Compound ◽  
Catalytic Amount ◽  
Side Chain ◽  
Hydroxyl Groups ◽  
Chemical Behavior ◽  
Model Compounds ◽  
Protection Method ◽  
Convenient Synthesis ◽  
Lignin Model ◽  
Convenient Preparation

Abstract Lignin, as the second most abundant biopolymer on earth, is one of the targets for plant biorefinery studies. Its complex chemical behavior is frequently studied by dimeric, trimeric, etc. model compounds, preferably with a β-O-4-type structure. In the present study, a convenient synthesis of a β-O-4-type trimeric model compound possessing a free syringylic hydroxyl has been investigated. Two key modifications were in focus: (1) Protection of the aliphatic hydroxyl groups of the starting phenolic dimer prior to the SN2 displacement reaction before introducing the syringylic moiety with 2,2-dimethoxypropane. (2) The hydroxymethylation step to introduce the full side chain moiety. When this reaction was performed in dioxane/water in the presence of a catalytic amount of KOH instead of K2CO3, the formation of a side product via dehydration was markedly reduced. In addition, a convenient method for introducing an α,β-epoxide structure in acetophenone is recommended.

scholarly journals DERA in Flow: Synthesis of a Statin Side Chain Precursor in Continuous Flow Employing Deoxyribose-5-Phosphate Aldolase Immobilized in Alginate-Luffa Matrix

Catalysts ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 137 ◽  
Author(s):  
Bianca Grabner ◽  
Yekaterina Pokhilchuk ◽  
Heidrun Gruber-Woelfler
Keyword(s):  
Renewable Resources ◽  
Continuous Flow ◽  
Ph Value ◽  
Continuous Process ◽  
Side Chain ◽  
Hydroxyl Groups ◽  
Inexpensive Method ◽  
Reaction Conditions ◽  
Flow Process ◽  
Artery Disease

Statins, cholesterol-lowering drugs used for the treatment of coronary artery disease (CAD), are among the top 10 prescribed drugs worldwide. However, the synthesis of their characteristic side chain containing two chiral hydroxyl groups can be challenging. The application of deoxyribose-5-phosphate aldolase (DERA) is currently one of the most promising routes for the synthesis of this side chain. Herein, we describe the development of a continuous flow process for the biosynthesis of a side chain precursor. Design of experiments (DoE) was used to optimize the reaction conditions (pH value and temperature) in batch. A pH of 7.5 and a temperature of 32.5 °C were identified to be the optimal process settings within the reaction space considered. Additionally, an immobilization method was developed using the alginate-luffa matrix (ALM), which is a fast, simple, and inexpensive method for enzyme immobilization. Furthermore, it is non-toxic, biodegradable, and from renewable resources. The final continuous process was operated stable for 4 h and can produce up to 4.5 g of product per day.

New Host-Guest Polymeric System for Thermal Stability Enhancement of Electro Optic Effect

2002 ◽  
Vol 725 ◽  
Author(s):  
Seung Koo Park ◽  
Jung Yun Do ◽  
Jung-Jin Ju ◽  
Suntak Park ◽  
Myung-Hyun Lee
Keyword(s):  
Thermal Stability ◽  
Model Compound ◽  
Main Chain ◽  
Side Chain ◽  
Hydroxyl Groups ◽  
New Host ◽  
Polymer Main Chain ◽  
Electro Optic ◽  
Chromophore Concentration ◽  
Stability Enhancement

AbstractA new host-guest electro optic (EO) polymer, in which a chromophore can be reacted with the polymer main chain during poling to give the corresponding side-chain EO polymer, has been prepared for improving EO effect and its thermal stability. Polyisoimide (PII) synthesized from 2, 2-bis (4-aminophenyl) hexafluoropropane and oxydiphthalic anhydride and Disperse Red 1 (DR1) were used as a host and a guest, respectively. A model compound reaction and Infrared spectra of the host-guest film after annealing at various temperatures show that the reaction between the isoimide groups in PII and the hydroxyl groups in DR1 occurs around 140 °C. The glass transition temperatures of the resulting EO polyamic aicd ester-imide copolymer with 0, 10, 20 and 30 wt. % of chromophore concentration were 275, 219, 160, and 124 °C, respectively. The EO coefficient obtained at a wavelength of 1.55 νm was 5.3 and 10.5 pm/V from the EO polymer film with 20 and 30 wt. % DR1. The EO signals exhibited only a slight decay at high temperature due to the chemical reaction between the host and guest during poling.

scholarly journals Conformation and supramolecular arrangement of 1,3:2,4-dibenzyli-dene-D-sorbitol in solution and in single crystals

2021 ◽  
Author(s):  
Fernán Berride ◽  
Victor M. Sánchez-Pedregal ◽  
Bruno Dacuña ◽  
Eurico Cabrita ◽  
Armando Navarro-Vázquez ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Nmr Spectroscopy ◽  
Van Der Waals Interactions ◽  
Side Chain ◽  
Water Molecules ◽  
Hydroxyl Groups ◽  
Intermolecular Hydrogen Bonds ◽  
X Ray ◽  
Definitive Evidence ◽  
Phenyl Rings

The X-ray crystal structure of the gelator 1,3:2,4-dibenzylidene-D-sorbitol (DBS) is reported here. DBS is an important gelating molecule known for nearly 130 years, that has eluded crystallization until now. The crystal obtained presents an axial stacking of DBS molecules stabilized by both Van der Waals interactions and intermolecular hydrogen bonds of the side chain hydroxyl groups with either neighboring DBS or water molecules. The crystal structure shows definitive evidence for the frequently assumed “butterfly” type aggregation mode and experimentally proves the equatorial placement of the phenyl rings. The conformation of DBS has been analyzed in the crystal structure and compared with that determined in solution through NMR spectroscopy.

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