13C–14N REAPDOR and 13C–2D θ-REDOR NMR on a blend of tri-p-tolylamine and bisphenol-A-polycarbonate

Kesling, Brian; Hughes, E. W.; Gullion, Terry

doi:10.1016/s0926-2040(00)00049-7

Cited by 12 publications

(6 citation statements)

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“…A similar relaxation result is reported for poly(vinylphenol-co-methyl methacrylate) with poly-(ethylene oxide) (127). Blends of poly(vinyl chloride) with other materials have been studied with 13 C NMR (128), as have blends of tri-p-tolylamine with bisphenol A-polycarbonate (129), phenolic resins with the bis(hydroxy ether) of bisphenol A (130), and polystyrene blends (131).…”

Section: Synthetic Polymerssupporting

confidence: 57%

Solid-State Nuclear Magnetic Resonance

2002

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Section: Synthetic Polymerssupporting

confidence: 57%

Solid-State Nuclear Magnetic Resonance

2002

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“…The application of spin- 1 / 2 to 2 H REDOR measurements reported here extends the available methods for determining torsion angles from internuclear distances. ,,, Heteronuclear distance measurements between a spin- 1 / 2 nucleus (X) and a spin-1 deuterium ( 2 H) can be achieved during magic angle spinning (MAS) by reintroducing dipolar couplings using a variation of Rotational Echo Double Resonance (REDOR). − Use of deuterium phase modulated rf-pulses (PM5) to reintroduce X− 2 H dipolar interactions and determine internuclear distances was demonstrated for l -alanine- 2 - d 1 and ethyl malonic acid- 4 - d 2 . A simple and powerful scheme for determining peptide backbone torsion angles is to incorporate commercially available amino acids that contain a nonexchangeable deuterium atom bound to the α carbon (Figure ).…”

Section: Introductionmentioning

confidence: 99%

Solid-State NMR Determination of Peptide Torsion Angles: Applications of ²H-Dephased REDOR

et al. 2000

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The backbone conformation of peptides and proteins is completely defined by the torsion angles (φ,ψ,ω) of each amino acid residue along the polypeptide chain. We demonstrate a solid-state NMR method based on heteronuclear distance measurements for determining (φ,ψ) angles. Simple and reliable deuterium phase modulated pulses (PM5) reintroduce dipolar couplings between 2H and a spin-1/2 nucleus. Measuring the 13C i- 1{2H i α} REDOR distance across a peptide bond results in the torsion angle φ i as a consequence of the restricted geometry of the peptide backbone. The 15N i+ 1{2H i α} REDOR distance across a peptide bond defines the torsion angle ψ i . This approach is demonstrated for both the 3-spin X{2H2}REDOR case of glycine and the 2-spin X{2H}REDOR case, represented by l-alanine, using two different tripeptides. It is shown that the technique can handle multiple sample conformations. PM5-REDOR decay curves of the ψ angle show distinctly different behaviors between α-helix and β-sheet backbone conformations.

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“…In contrast to the situation for 13 C− 15 N REDOR, dephasing in 13 C{ 17 O} REAPDOR depends on a large number of parameters, − including the quadrupolar coupling constant and asymmetry parameter, the spinning speed, the radiofrequency irradiation strength, and the relative orientation of the 13 C− 17 O internuclear vector and the 17 O quadrupolar tensor. Nevertheless, observed and calculated dephasing can be used to extract internuclear distances as long as the radiofrequency amplitude and the sample rotation speed satisfy an adiabaticity condition .…”

Section: Materials and Experimental Methodsmentioning

confidence: 97%

Oxygen-17 Appears Only in Protein in Water-Stressed Soybean Leaves Labeled by ¹⁷O₂

Gullion

Singh

et al. 2010

J. Am. Chem. Soc.

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We have used a rotational-echo adiabatic-passage double-resonance (13)C{(17)O} solid-state NMR experiment to prove that the glycine produced in the oxygenase reaction of ribulose bisphosphate carboxylase-oxygenase is incorporated exclusively into protein (or protein precursors) of intact, water-stressed soybean leaves exposed to (13)CO(2) and (17)O(2). The water stress increased stomatal resistance and decreased gas exchange so that the Calvin cycle in the leaf chloroplasts was no more than 35% (13)C isotopically enriched. Labeled O(2) levels were sufficient, however, to increase the (17)O isotopic concentration of oxygenase products 20-fold over the natural-abundance level of 0.04%. The observed direct incorporation of glycine into protein shows that water stress suppresses photorespiration in soybean leaves.

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13C–14N REAPDOR and 13C–2D θ-REDOR NMR on a blend of tri-p-tolylamine and bisphenol-A-polycarbonate

Cited by 12 publications

References 11 publications

Solid-State Nuclear Magnetic Resonance

Solid-State Nuclear Magnetic Resonance

Solid-State NMR Determination of Peptide Torsion Angles: Applications of ²H-Dephased REDOR

Oxygen-17 Appears Only in Protein in Water-Stressed Soybean Leaves Labeled by ¹⁷O₂

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13C–14N REAPDOR and 13C–2D θ-REDOR NMR on a blend of tri-p-tolylamine and bisphenol-A-polycarbonate

Cited by 12 publications

References 11 publications

Solid-State Nuclear Magnetic Resonance

Solid-State Nuclear Magnetic Resonance

Solid-State NMR Determination of Peptide Torsion Angles: Applications of 2H-Dephased REDOR

Oxygen-17 Appears Only in Protein in Water-Stressed Soybean Leaves Labeled by 17O2

Contact Info

Product

Resources

About

Solid-State NMR Determination of Peptide Torsion Angles: Applications of ²H-Dephased REDOR

Oxygen-17 Appears Only in Protein in Water-Stressed Soybean Leaves Labeled by ¹⁷O₂