Two-dimensional rotational spin-echo nuclear magnetic resonance in solids: correlation of chemical shift and dipolar interactions

Munowitz, M.; Griffin, Robert G.; Bodenhausen, Geoffrey; Huang, Tai-huang

doi:10.1021/ja00400a007

Cited by 375 publications

(249 citation statements)

References 0 publications

Supporting

Mentioning

245

Contrasting

Unclassified

Order By: Relevance

“…38 These experiments were conducted at 298 K, above the phase-transition temperatures of the membranes. Figures 3 and 4 show the 13 C− 1 H dipolar dephasing curves of CT and LT, respectively.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Aggregation and Dynamics of Oligocholate Transporters in Phospholipid Bilayers Revealed by Solid-State NMR Spectroscopy

et al. 2012

View full text Add to dashboard Cite

Macrocycles made of cholate building blocks were previously found to transport glucose readily across lipid bilayers. In this study, an 15N, 13Cα-labeled glycine was inserted into a cyclic cholate trimer and attached at the end of a linear trimer, respectively. The isotopic labeling allowed us to use solid-state NMR spectroscopy to study the dynamics, aggregation, and depth of insertion of these compounds in lipid membranes. The cyclic compound was found to be mostly immobilized in DLPC, POPC/POPG, and POPC/POPG/cholesterol membranes, whereas the linear trimer displayed large-amplitude motion that depended on the membrane thickness and viscosity. 13C-detected 1H spin diffusion experiments revealed the depth of insertion of the compounds in the membranes, as well as their contact with water molecules. The data support a consistent stacking model for the cholate macrocycles in lipid membranes, driven by the hydrophobic interactions of the water molecules in the interior of the macrocycles. The study also shows a strong preference of the linear trimer for the membrane surface, consistent with its lack of transport activity in earlier liposome leakage assays. Disciplines Chemistry CommentsReprinted (adapted) with permission from Langmuir 28 (2012) ABSTRACT: Macrocycles made of cholate building blocks were previously found to transport glucose readily across lipid bilayers. In this study, an 15 N, 13 Cα-labeled glycine was inserted into a cyclic cholate trimer and attached at the end of a linear trimer, respectively. The isotopic labeling allowed us to use solid-state NMR spectroscopy to study the dynamics, aggregation, and depth of insertion of these compounds in lipid membranes. The cyclic compound was found to be mostly immobilized in DLPC, POPC/POPG, and POPC/POPG/cholesterol membranes, whereas the linear trimer displayed large-amplitude motion that depended on the membrane thickness and viscosity. 13 C-detected 1 H spin diffusion experiments revealed the depth of insertion of the compounds in the membranes, as well as their contact with water molecules. The data support a consistent stacking model for the cholate macrocycles in lipid membranes, driven by the hydrophobic interactions of the water molecules in the interior of the macrocycles. The study also shows a strong preference of the linear trimer for the membrane surface, consistent with its lack of transport activity in earlier liposome leakage assays.

show abstract

Section: ■ Results and Discussionmentioning

confidence: 99%

Aggregation and Dynamics of Oligocholate Transporters in Phospholipid Bilayers Revealed by Solid-State NMR Spectroscopy

et al. 2012

View full text Add to dashboard Cite

show abstract

“…This coupling strength corresponds to a C a -H a distance of 1.095 6 0.033 Å , in good agreement with previous distance determinations. 57 Values of |ð3 cos 2 h À 1Þ=2| for A10, L11, A14, I16, A18, and V25 are then 0.24 6 0.05, 0.15 6 0.07, 0.22 6 0.03, 0.09 6 0.04, 0.24 6 0.03, and 0.33 6 0.05, respectively.…”

Section: Structural Constraints From Solid-state Nmrmentioning

confidence: 98%

Oligomerization state and supramolecular structure of the HIV‐1 Vpu protein transmembrane segment in phospholipid bilayers

et al. 2010

View full text Add to dashboard Cite

HIV-1 Vpu is an 81-residue protein with a single N-terminal transmembrane (TM) helical segment that is involved in the release of new virions from host cell membranes. Vpu and its TM segment form ion channels in phospholipid bilayers, presumably by oligomerization of TM helices into a pore-like structure. We describe measurements that provide new constraints on the oligomerization state and supramolecular structure of residues 1-40 of Vpu (Vpu 1-40 ), including analytical ultracentrifugation measurements to investigate oligomerization in detergent micelles, photo-induced crosslinking experiments to investigate oligomerization in bilayers, and solid-state nuclear magnetic resonance measurements to obtain constraints on intermolecular contacts between and orientations of TM helices in bilayers. From these data, we develop molecular models for Vpu TM oligomers. The data indicate that a variety of oligomers coexist in phospholipid bilayers, so that a unique supramolecular structure can not be defined. Nonetheless, since oligomers of various sizes have similar intermolecular contacts and orientations, molecular models developed from our data are most likely representative of Vpu TM oligomers that exist in host cell membranes.

show abstract

“…13 C-1 H DIPSHIFT experiments were carried out at 298 K under 7 kHz MAS to measure motional amplitudes (Munowitz et al, 1981). 1 H homonuclear decoupling was achieved using FSLG with a 1 H transverse field strength of 80 kHz.…”

Section: Ssnmr Spectroscopymentioning

confidence: 99%

Gradients in Wall Mechanics and Polysaccharides along Growing Inflorescence Stems

et al. 2017

View full text Add to dashboard Cite

At early stages of Arabidopsis (Arabidopsis thaliana) flowering, the inflorescence stem undergoes rapid growth, with elongation occurring predominantly in the apical ;4 cm of the stem. We measured the spatial gradients for elongation rate, osmotic pressure, cell wall thickness, and wall mechanical compliances and coupled these macroscopic measurements with molecular-level characterization of the polysaccharide composition, mobility, hydration, and intermolecular interactions of the inflorescence cell wall using solid-state nuclear magnetic resonance spectroscopy and small-angle neutron scattering. Force-extension curves revealed a gradient, from high to low, in the plastic and elastic compliances of cell walls along the elongation zone, but plots of growth rate versus wall compliances were strikingly nonlinear. Neutron-scattering curves showed only subtle changes in wall structure, including a slight increase in cellulose microfibril alignment along the growing stem. In contrast, solid-state nuclear magnetic resonance spectra showed substantial decreases in pectin amount, esterification, branching, hydration, and mobility in an apical-to-basal pattern, while the cellulose content increased modestly. These results suggest that pectin structural changes are connected with increases in pectin-cellulose interaction and reductions in wall compliances along the apical-to-basal gradient in growth rate. These pectin structural changes may lessen the ability of the cell wall to undergo stress relaxation and irreversible expansion (e.g. induced by expansins), thus contributing to the growth kinematics of the growing stem.

show abstract

Two-dimensional rotational spin-echo nuclear magnetic resonance in solids: correlation of chemical shift and dipolar interactions

Cited by 375 publications

References 0 publications

Aggregation and Dynamics of Oligocholate Transporters in Phospholipid Bilayers Revealed by Solid-State NMR Spectroscopy

Aggregation and Dynamics of Oligocholate Transporters in Phospholipid Bilayers Revealed by Solid-State NMR Spectroscopy

Oligomerization state and supramolecular structure of the HIV‐1 Vpu protein transmembrane segment in phospholipid bilayers

Gradients in Wall Mechanics and Polysaccharides along Growing Inflorescence Stems

Contact Info

Product

Resources

About