Journal ArticleDOI
Site-Resolved Determination of Peptide Torsion Angle O from the Relative Orientations of Backbone N-H and C-H Bonds by Solid-State NMR
TLDR
In this paper, a rotational sideband spectrum of the sum and difference of the two corresponding dipolar couplings is used to determine the torsion angle φ in peptides.Abstract:
We describe a method for determining the torsion angle φ in peptides. The technique is based on the measurement of the relative orientation of the N−HN and Cα−Hα bonds, which is manifested in the rotational sideband spectrum of the sum and difference of the two corresponding dipolar couplings. The method exploits 15N−13C double-quantum and zero-quantum coherences, which evolve simultaneously under the N−H and C−H dipolar interactions. The magnitudes of these dipolar couplings scaled by the proton homonuclear decoupling sequence are directly extracted from control experiments that correlate the dipolar interactions with the isotropic chemical shifts. Applied to 15N-labeled N-acetyl-d,l-valine, the experiment yielded φ = −135°, which agrees well with the X-ray crystal structure. Simulations indicate that the accuracy of the measured angle φ is within ±10° when the N−HN and Cα−Hα bonds are approximately antiparallel and ±20° when they are roughly parallel. The technique is sufficiently sensitive to be applie...read more
Citations
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Journal ArticleDOI
High-resolution molecular structure of a peptide in an amyloid fibril determined by magic angle spinning NMR spectroscopy
Christopher P. Jaroniec,Cait E. MacPhee,Vikram S. Bajaj,Michael T. McMahon,Christopher M. Dobson,Robert G. Griffin +5 more
TL;DR: The results indicate that TTR(105-115) adopts an extended beta-strand conformation in the amyloid fibrils such that both the main- and side-chain torsion angles are close to their optimal values.
Journal ArticleDOI
Advanced solid-state NMR methods for the elucidation of structure and dynamics of molecular, macromolecular, and supramolecular systems.
Journal ArticleDOI
Fivefold symmetric homonuclear dipolar recoupling in rotating solids: Application to double quantum spectroscopy
TL;DR: In this paper, a double quantum recoupling is explored in multiple spin systems and derived analytical forms for polarization transfer and double quantum excitation relevant for uniformly labeled systems, and the wide applicability of the fivefold sequence is demonstrated with INADEQUATE type spectra of uniformly 13 C labeled sucrose and L-alanine.
Journal ArticleDOI
Dipolar recoupling in MAS spectra of biological solids.
TL;DR: Dipolar recoupling yields solid state NMR spectral assignments and provides constraints on internuclear distances and torsion angles and offers a fresh approach to structural studies of a variety of systems that cannot be examined with conventional tools.
References
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Book
Proteins: Structures and Molecular Properties
TL;DR: This paper discusses the physical properties of polypeptides, the structure of which has been determined Crystallographically to High Resolution and its role in the biosynthesis of Proteins.
Journal ArticleDOI
Contact Electron‐Spin Coupling of Nuclear Magnetic Moments
TL;DR: In this article, the valence-bond theory for the contact electron-spin coupling of nuclear magnetic moments is used to calculate the proton−proton, proton-fluorine, and fluorine-florine coupling constants in ethanic and ethylenic molecules.
Journal ArticleDOI
Solution of the Schrödinger Equation with a Hamiltonian Periodic in Time
TL;DR: In this article, the interaction of a quantum system with an oscillating field is studied in a formalism which replaces the semiclassical time-dependent Hamiltonian with a time-independent Hamiltonian represented by an infinite matrix.
Journal ArticleDOI
Correlation of proton and nitrogen-15 chemical shifts by multiple quantum NMR☆
TL;DR: In this paper, the correlation of 1H and 15N chemical shifts based on zero and double quantum NMR is discussed. And the indirect determination of nitrogen shifts from the proton signals provides a dramatic gain in sensitivity over direct observation of 15N signals, and examples are given of applications of the methods to samples with natural abundance 15N concentration and to a sample of 0.7 mM 65% 15N enriched tRNA in H2O.
Journal ArticleDOI
NMR in rotating solids
M. Matti Maricq,John S. Waugh +1 more
TL;DR: In this paper, it was shown that rotational spin echoes provide a convenient means of studying very slow random molecular rotations (τc≲1 sec), which must be described by a proper average Hamiltonian theory.