scholarly journals Pressure-induced association of oleic acid (OA) under varying temperature studied by multiple-perturbation two-dimensional (2D) IR correlation spectroscopy

2012 ◽  
Vol 1028 ◽  
pp. 164-169 ◽  
Author(s):  
Hideyuki Shinzawa ◽  
Takuma Genkawa ◽  
Wataru Kanematsu
Keyword(s):  
Oleic Acid ◽  
Correlation Spectroscopy ◽  
Two Dimensional ◽  
2D Ir

Two-Dimensional Infrared and Near-Infrared Correlation Spectroscopy: Applications to Studies of Temperature-Dependent Spectral Variations of Self-Associated Molecules

1997 ◽  
Vol 51 (4) ◽  
pp. 526-535 ◽  
Author(s):  
Yukihiro Ozaki ◽  
Yongliang Liu ◽  
Isao Noda
Keyword(s):  
Near Infrared ◽  
Oleyl Alcohol ◽  
Correlation Spectroscopy ◽  
Intensity Change ◽  
Pure Liquid ◽  
Two Dimensional ◽  
Temperature Dependent ◽  
Thermally Induced ◽  
2D Ir ◽  
Almost All

This paper demonstrates the potential of generalized two-dimensional (2D) Fourier transform (FT) infrared (IR) and near-infrared (NIR) correlation spectroscopy in the studies of temperature-dependent spectral variations of self-associated molecules. Three examples of the 2D correlation analysis are discussed in this paper. The first two are concerned with the temperature-dependent IR and NIR spectral changes of N-methylacetamide (NMA) in the pure liquid state. The 2D IR correlation approach revealed that almost all the peaks of NMA in the 3400–1100-cm−1 region consist of two to four separate bands. For example, the amide I band contains contributions from at least four distinct bands at 1685, 1665, 1650, and 1635 cm−1. The analysis of the asynchronous 2D IR spectrum in the amide I region showed that the sequence of spectral intensity change in the ascending order of temperature was given by 1635<1650<1665<1685 cm−1. These bands at 1635, 1650, 1665, and 1685 cm−1 were assigned to the amide I modes of chain oligomers of various sizes and dimer of NMA; the longer the chain, the lower the frequency. The closeup view of 2D NIR correlation spectra of NMA obtained at narrow spectral and temperature windows enabled us to propose not only band assignments in the 6800–6050-cm−1 region but also a detailed mechanistic picture of the thermally induced dissociation of NMA for each temperature range. We also applied the generalized 2D correlation approach to the analysis of a set of FT NIR spectra of oleyl alcohol under temperature variations. The 2D NIR analysis enhanced the spectral resolution and simplified the spectra with overlapped bands. For example, it was found that a band at 7090 cm−1 arising from the first overtone of an OH stretching mode of the monomeric alcohol consists of two bands due to the rotational isomerism of the free OH group. An intriguing possibility of correlating various overtone and fundamental bands to establish unambiguous assignments was also suggested from the 2D NIR study on oleyl alcohol.

scholarly journals Two-dimensional IR correlation spectroscopy of mutants of the β-glycosidase from the hyperthermophilic archaeon Sulfolobus solfataricus identifies the mechanism of quaternary structure stabilization and unravels the sequence of thermal unfolding events

2004 ◽  
Vol 384 (1) ◽  
pp. 69-78 ◽  
Author(s):  
Alessio AUSILI ◽  
Barbara DI LAURO ◽  
Beatrice COBUCCI-PONZANO ◽  
Enrico BERTOLI ◽  
Andrea SCIRÈ ◽  
...  
Keyword(s):  
Quaternary Structure ◽  
Ion Pairs ◽  
Sulfolobus Solfataricus ◽  
Correlation Spectroscopy ◽  
Glycoside Hydrolases ◽  
Thermal Unfolding ◽  
Two Dimensional ◽  
Wild Type ◽  
Hyperthermophilic Archaeon ◽  
2D Ir

β-Glycosidase from the hyperthermophilic archaeon Sulfolobus solfataricus is a homotetramer with a higher number of ion pairs compared with mesophilic glycoside hydrolases. The ion pairs are arranged in large networks located mainly at the tetrameric interface of the molecule. In the present study, the structure and thermal stability of the wild-type β-glycosidase and of three mutants in residues R488 and H489 involved in the C-terminal ionic network were examined by FTIR (Fourier-transform IR) spectroscopy. The FTIR data revealed small differences in the secondary structure of the proteins and showed a lower thermostability of the mutant proteins with respect to the wild-type. Generalized 2D-IR (two-dimensional IR correlation spectroscopy) at different temperatures showed different sequences of thermal unfolding events in the mutants with respect to the wild-type, indicating that punctual mutations affect the unfolding and aggregation process of the protein. A detailed 2D-IR analysis of synchronous maps of the proteins allowed us to identify the temperatures at which the ionic network that stabilizes the quaternary structure of the native and mutant enzymes at the C-terminal breaks down. This evidence gives support to the current theories on the mechanism of ion-pair stabilization in proteins from hyperthermophilic organisms.

scholarly journals Two-dimensional infrared correlation spectroscopy studies on secondary structures and hydrogen bondings of side chains of proteins

2003 ◽  
Vol 17 (2-3) ◽  
pp. 79-100 ◽  
Author(s):  
Yukihiro Ozaki ◽  
Koichi Murayama ◽  
Yuqing Wu ◽  
Boguslawa Czarnik-Matusewicz
Keyword(s):  
Secondary Structures ◽  
Correlation Spectroscopy ◽  
Side Chains ◽  
Two Dimensional ◽  
2D Ir ◽  
Intensity Changes ◽  
Specific Order ◽  
Spectroscopy Studies ◽  
2D Correlation Spectroscopy ◽  
Hydrogen Bondings

This review paper reports usefulness of two-dimensional (2D) correlation spectroscopy in analyzing infrared (IR) spectra of proteins in aqueous solutions. In the 2D approach, spectral peaks are spread over the second dimension, thereby simplifying the visualization of complex spectra consisting of many overlapped bands, and enhancing spectral resolution. 2D correlation spectroscopy has a powerful deconvolution ability for highly overlapped amide I, amide II, and amide III bands of proteins, enabling these bands to be assigned to various secondary structures. It also provides the specific order of the spectral intensity changes taking place during the measurement on the value of controlling variable affecting the spectra. Therefore, one can monitor the order of secondary structure variations in proteins by using 2D IR correlation spectroscopy. 2D correlation spectroscopy also provides new insight into the hydrogen bondings of side chains of proteins. In this review the principles and advantages of 2D correlation spectroscopy are outlined first and then three examples of the applications of 2D IR spectroscopy to protein research are presented.

Recent Developments in Two-Dimensional Infrared (2D IR) Correlation Spectroscopy

1993 ◽  
Vol 47 (9) ◽  
pp. 1317-1323 ◽  
Author(s):  
I. Noda ◽  
A. E. Dowrey ◽  
C. Marcott
Keyword(s):  
Ir Spectroscopy ◽  
Ir Spectra ◽  
Correlation Method ◽  
External Perturbation ◽  
Correlation Spectroscopy ◽  
Two Dimensional ◽  
2D Ir ◽  
Different Types ◽  
Recent Developments ◽  
Arbitrary Time Dependence

Recent developments in two-dimensional infrared (2D IR) correlation spectroscopy are reviewed. Since the initial introduction of the basic concept seven years ago, the field of 2D IR spectroscopy has evolved considerably. The method for generating 2D IR spectra from perturbation-induced time-dependent fluctuations of IR intensities and the properties of such 2D spectra are summarized first. Applications of 2D IR spectroscopy are then surveyed, and improvements in the instrumentation are reviewed. Different types of external perturbation schemes capable of inducing dynamic fluctuations of IR spectra are listed. Finally, a new 2D correlation method for dynamic spectral data with arbitrary time-dependence is discussed.

Transient 2D IR Correlation Spectroscopy of the Photopolymerization of Acrylic and Epoxy Monomers

1993 ◽  
Vol 47 (9) ◽  
pp. 1337-1342 ◽  
Author(s):  
Tatsuhiko Nakano ◽  
Shigeru Shimada ◽  
Rieko Saitoh ◽  
Isao Noda
Keyword(s):  
Fourier Transform ◽  
Real Time ◽  
Correlation Spectroscopy ◽  
Spectral Intensity ◽  
Two Dimensional ◽  
2D Ir ◽  
Intensity Changes ◽  
Ft Ir ◽  
Arbitrary Waveform ◽  
Reaction Processes

Transient two-dimensional infrared (2D IR) correlation spectroscopy coupled with real-time Fourier transform infrared (RT FT-IR) measurement was used to analyze the reaction processes of photopolymerization systems. Unlike the previously developed 2D IR methods based on sinusoidally varying IR signals, a newly developed 2D correlation formalism applicable to transient spectroscopic signals having an arbitrary waveform was used. By this method, features associated with spectral intensity changes and peak shifts arising from polymerization reactions were clearly observed.

scholarly journals A two‒dimensional IR spectroscopic (2D‒IR) simulation of protein conformational changes

2004 ◽  
Vol 18 (1) ◽  
pp. 49-58 ◽  
Author(s):  
José Luis R. Arrondo ◽  
Ibon Iloro ◽  
Julián Aguirre ◽  
Félix M. Goñi
Keyword(s):  
Conformational Changes ◽  
Intensity Variation ◽  
Correlation Spectroscopy ◽  
Two Dimensional ◽  
2D Ir ◽  
Symmetric Pattern ◽  
Band Position ◽  
Intensity Changes ◽  
Novel Method ◽  
Ir Spectroscopic

Two‒dimensional IR correlation spectroscopy (2D‒IR) is a novel method that provides the analysis of infrared spectra with the capacity to differentiate overlapping peaks and to distinguish between in‒phase and out‒of‒phase spectral responses. Artificial spectra originated from protein amide I band component parameters have been used to study their variation in the correlation maps. Using spectra composed of one, two or three Gaussian peaks, behaviour patterns of the bands in the synchronous and asynchronous maps have been originated, with changes in intensity, band position and bandwidth. Intensity changes produce high‒intensity spots in the synchronous spectra, whereas only noise is observed in the asynchronous spectra. Band shifting originates more complex patterns. In synchronous spectra, several spots are generated at the beginning and at the end of the shifting band. Also, characteristic asynchronous spectra with butterfly‒like shapes are formed showing the trajectory of the shift. Finally, synchronous maps corresponding to band broadening reveal several spots at peak inflection points, related to the zones with higher intensity variation. The asynchronous spectra are very complex but they follow a characteristic symmetric pattern. Furthermore, examples of maps obtained from polypeptides and proteins using temperature as the perturbing factor are interpreted in terms of the patterns obtained from artificial bands.

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