Metalloporphyrin gas and condensed-phase resonance Raman studies: the role of vibrational anharmonicities as determinants of Raman frequencies

1983 ◽  
Vol 105 (25) ◽  
pp. 7244-7251 ◽  
Author(s):  
Sanford A. Asher ◽  
James Murtaugh
Keyword(s):  
Condensed Phase ◽  
Resonance Raman ◽  
Phase Resonance

scholarly journals Protein crystal lattices are dynamic assemblies: the role of conformational entropy in the protein condensed phase

IUCrJ ◽  
2018 ◽  
Vol 5 (2) ◽  
pp. 130-140 ◽  
Author(s):  
Margarita Dimova ◽  
Yancho D. Devedjiev
Keyword(s):  
Condensed Phase ◽  
Protein Structures ◽  
Van Der Waals Interactions ◽  
Protein Crystal ◽  
Crystal Formation ◽  
Conformational Entropy ◽  
Crystal Lattices ◽  
Crystal Contacts ◽  
First Time

Until recently, the occurrence of conformational entropy in protein crystal contacts was considered to be a very unlikely event. A study based on the most accurately refined protein structures demonstrated that side-chain conformational entropy and static disorder might be common in protein crystal lattices. The present investigation uses structures refined using ensemble refinement to show that although paradoxical, conformational entropy is likely to be the major factor in the emergence and integrity of the protein condensed phase. This study reveals that the role of shape entropy and local entropic forces expands beyond the onset of crystallization. For the first time, the complete pattern of intermolecular interactions by protein atoms in crystal lattices is presented, which shows that van der Waals interactions dominate in crystal formation.

Reactions of aromatic structures in brightness reversion of fully-bleached eucalyptus kraft pulps

Holzforschung ◽  
2009 ◽  
Vol 63 (3) ◽  
Author(s):  
Anna-Stiina Jääskeläinen ◽  
Katri Toikka ◽  
Anni Lähdetie ◽  
Tiina Liitiä ◽  
Tapani Vuorinen
Keyword(s):  
Resonance Raman ◽  
Kraft Pulps ◽  
Brightness Reversion ◽  
Vis Spectroscopy ◽  
Uv Resonance Raman ◽  
Hexenuronic Acid

Abstract The role of aromatic structures in brightness reversion of fully bleached pulps was studied by UV resonance Raman (UVRR) and reflectance UV-Vis spectroscopy. The results clearly showed that ageing increased the aromatic band at approximately 1600 cm-1 in the UVRR spectra and the lignin band at approximately 280 nm in the UV-Vis spectra. This increase was probably due to increased conjugation of lignin and it was observed for all pulps regardless of the bleaching sequence. In addition to these lignin reactions, other unsaturated structures, such as hexenuronic acid groups, reacted during ageing.

Structural chemistry involved in information detection and transmission by gas sensor heme proteins: Resonance Raman investigation

2008 ◽  
Vol 80 (12) ◽  
pp. 2667-2678 ◽  
Author(s):  
Samir F. El-Mashtoly ◽  
Teizo Kitagawa
Keyword(s):  
Gas Sensor ◽  
Structural Changes ◽  
Catalytic Domain ◽  
Signal Transmission ◽  
Resonance Raman ◽  
Protein Activity ◽  
Sensor Proteins ◽  
Vinyl Group ◽  
Protein Moiety

A variety of heme-containing gas sensor proteins have been discovered by gene analysis from bacteria to mammals. In general, these proteins are composed of an N-terminal heme-containing sensor domain and a C-terminal catalytic domain. Binding of O2, CO, or NO to the heme causes a change in the structure of heme, which alters the protein conformation in the vicinity of the heme, and the conformational change is propagated to the catalytic domain, leading to regulation of the protein activity. This mini-review summarizes the recent resonance Raman studies obtained with both visible and UV excitation sources for two O2 sensor proteins, EcDOS and HemAT-Bs. These investigations have shown the role of heme propionate hydrogen-bonding interactions in communicating the heme structural changes, which occur upon ligand binding, from heme to the protein moiety. Furthermore, it is deduced that the contact interactions between the heme 2-vinyl group and the surrounding residues are also important for signal transmission from heme to protein in EcDOS.

Flame Retardancy of Polymers: The Role of Specific Reactions in the Condensed Phase

2015 ◽  
Vol 301 (1) ◽  
pp. 9-35 ◽  
Author(s):  
Bernhard Schartel ◽  
Birgit Perret ◽  
Bettina Dittrich ◽  
Michael Ciesielski ◽  
Johannes Krämer ◽  
...  
Keyword(s):  
Condensed Phase ◽  
Flame Retardancy ◽  
Specific Reactions
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