Two-dimensional infrared spectroscopy

Noda, Isao

doi:10.1021/ja00203a008

Cited by 704 publications

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“…The first is by twodimensional mechanical/FTIR spectroscopy, where polarised FTIR is used to probe changes in the orientation of polymers in or out of phase with an applied, oscillating mechanical stress. This approach has been developed to a considerable degree of refinement for synthetic polymers by Noda [44], and appears to have great potential for characterising the internal deformation of the structure of the cell wall under mechanical stress.…”

Section: Vibrational (Infrared Absorption and Raman) Spectroscopymentioning

confidence: 99%

“…That is, the properties of the whole primary cell wall cannot be inferred by materials science from the properties of its components, because the wall is a nanostructure and not a material. Some of these problems may be soluble if the new methods based on vibrational spectroscopy [44,56] make it practicable to focus on stress-strain relationships in specific cell-wall polymers in situ.…”

Section: Cell Walls As Nanostructures: Functional Architecturementioning

confidence: 99%

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Macromolecular biophysics of the plant cell wall: Concepts and methodology

Jarvis

McCann

2000

Plant Physiology and Biochemistry

106

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-Plant cell walls provide form and mechanical strength to the living plant, but the relationship between their complex architecture and their remarkable ability to withstand external stress is not well understood. Primary cell walls are adapted to withstand tensile stresses while secondary cell walls also need to withstand compressive stresses. Therefore, while primary cell walls can with advantage be flexible and elastic, secondary cell walls must be rigid to avoid buckling under compressive loads. In addition, primary cell walls must be capable of growth and are subjected to cell separation forces at the cell corners. To understand how these stresses are resisted by cell walls, it will be necessary to find out how the walls deform internally under load, and how rigid are specific constituents of each type of cell wall. The most promising spectroscopic techniques for this purpose are solid-state nuclear magnetic resonance (NMR), and Fourier-transform infrared (FTIR) and Raman microscopy. By NMR relaxation experiments, it is possible to probe thermal motion in each cell-wall component. Novel adaptations of FTIR and Raman spectroscopy promise to allow mechanical stress and strain upon specific polymers to be examined in situ within the cell wall. © 2000 Éditions scientifiques et médicales Elsevier SAS Cellulose / growth / mobility / pectin CP, cross-polarisation / FT, Fourier-transform / IR, infrared / MAS, magic-angle spinning / NMR, nuclear magnetic resonance / T 2 , spin-spin relaxation time constant

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Section: Vibrational (Infrared Absorption and Raman) Spectroscopymentioning

confidence: 99%

Section: Cell Walls As Nanostructures: Functional Architecturementioning

confidence: 99%

Macromolecular biophysics of the plant cell wall: Concepts and methodology

Jarvis

McCann

2000

Plant Physiology and Biochemistry

106

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“…DIRLD data were later used in the development of a two-dimensional FTIR correlation technique. [35][36][37] This triple-modulation scheme, however, used a monochromator and required much time to compile spectra over an appreciable range of IR wave numbers. Wang et al 25 showed the use of step-scan mode Fourier transform (FT) spectroscopy to make time-resolved DIRLD measurements on isotactic polypropylene (iPP).…”

Section: Introductionmentioning

confidence: 99%

Rheooptical Fourier transform infrared spectroscopy of the deformation behavior in quenched and slow‐cooled isotactic polypropylene films

Parthasarthy

Sevegney

Kannan

2002

J Polym Sci B Polym Phys

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Emerging technological applications for complex polymers require insight into the dynamics of these materials from a molecular and nanostructural viewpoint. To characterize the orientational response at these length scales, we developed a versatile rheooptical Fourier transform infrared (FTIR) spectrometer by combining rheometry, polarimetry, and FTIR spectroscopy. This instrument is capable of measuring linear infrared dichroism spectra during both small-strain dynamic deformation and large-strain irreversible deformation over a wide temperature range. The deformation response of quenched and slow-cooled isotactic polypropylene (iPP) is investigated. In quenched iPP, under dynamic oscillatory strain at an amplitude of ϳ0.1%, the dichroism from the orientation of the amorphous chains is appreciably less than that from the crystalline region. At large irreversible strains, we measured the dichroic response for 12 different peaks simultaneously and quantitatively. The dichroism from the crystalline peaks is strong as compared to amorphous peaks. In the quenched sample, the dichroism from the crystalline region saturates at 50% strain, followed by a significant increase in the amorphous region dichroism. This is consistent with the notion that the crystalline regions respond strongly before the yield point, whereas the majority of postyielding orientation occurs in the amorphous region. Our results also suggest that the 841 cm Ϫ1 peak may be especially sensitive to the 'smectic' region orientation in the quenched sample. The response of the slow-cooled sample at 70°C is qualitatively similar but characterized by a stronger crystalline region dichroism and a weaker amorphous region dichroism, consistent with the higher crystallinity of this sample, and faster chain relaxation at 70°C.

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“…The author sincerely thanks Dr. Frank Prendergast for the generous supply of the 13 C labeled peptide. The author would also thank Dr McCormick's group in the synthesis and TOF-MS for the specifically labeled Ac-W(EAAAR) 5 A-NH 2. The work was supported in part by NIH-MBRS-SCORE…”

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confidence: 99%

Mechanism of Unfolding of A Model Helical Peptide

Pastrana-Rios

López

2002

The Scientific World JOURNAL

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INTRODUCTION.Synthetic model helical peptides, Acetyl-W(EAAAR) 5 A-amide with 13 C=O specifically labeled alanine segments in repeats n = 1,2 or 4,5 were studied in aqueous D 2 O solution as a function of temperature using Fourier transform infrared spectroscopy and twodimensional correlation analysis. The 13 C=O provided a probe which was sensitive to the carbonyl stretch in the peptide bonds of the alanine residues at the amino terminal end in one peptide as compared to the probe in the carboxy terminal end of the other peptide during thermal perturbation. The relative stability of each terminal end was examined; the more stable terminal was determined to be the amino terminal end. The 27-residue peptide was also simulated using parallel-tempering Monte Carlo simulations in the canonical ensemble. The peptide was modeled using the spring-bead interparticle potential coupled to a modified Lennard-Jones (L-J) potential that described the nonbonded interactions. The hydrogen bonding and salt bridge interactions were modeled by adjusting the attractive and repulsive parts of the L-J potential. Conformational changes were characterized by increments in the constant volume heat capacity, internal energy, and the radius of gyration of the peptide. METHOD.FT-IR experiments involved the use of fully H→D exchanged peptide redissolved in 1 mM phosphate buffer, 10 mM NaCl in 99.9% D, D 2 O at pD = 6.6. CaF 2 cells and a dualchamber, custom-milled cell holder connected to a Neslab circulating bath for temperature variation were used with an FTS-40 Bio-Rad (Cambridge, MA) equipped with custom shuttle and interface. Typically, 512 scans were coadded, apodized with a triangular function, and Fourier transformed to provide a resolution of 4 cm -1 , with data encoded every 2 cm -1 . Sixteen spectra were collected at sequential increments of temperature, allowing for thermal equilibrium. The spectra (in the spectral region of interest 1520-1750 cm -1 and 1300-1400 cm -1 ) were then analyzed using two-dimensional FT-IR correlation and curve-fitting. Two-dimensional FT-IR correlation analysis was performed using MathCad 2000 Professional (MathSoft, Inc., Cambridge, MA) software. The curve-fitting routines were done using Grams 3.01 (Galactic Industries Corp., Salem, NH) program. Origin 6 program was used to plot curvefitted data.Simulations were carried out using an SGI Origin 200. RESULTS.Structural and dynamic changes were investigated using FT-IR Isotope edited spectroscopy, two-dimensional correlation analysis (see Fig. 1) and molecular simulations. The arginine-glutamate salt bridge provides additional stability to the helical structure of this model peptide rendering it as a solid cylinder.The molecular simulations results agree very well with the experimental data obtained in that two conformational changes were observed. The first one occurs at low temperatures and corresponds to the unwinding of the amino terminal end and the second transition is associated to the unwinding of the carboxyl terminal end. A third transition...

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Two-dimensional infrared spectroscopy

Cited by 704 publications

References 0 publications

Macromolecular biophysics of the plant cell wall: Concepts and methodology

Macromolecular biophysics of the plant cell wall: Concepts and methodology

Rheooptical Fourier transform infrared spectroscopy of the deformation behavior in quenched and slow‐cooled isotactic polypropylene films

Mechanism of Unfolding of A Model Helical Peptide

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