Shape-persistent macrocycles — Self-assembly reactions and characterization by hyperpolarized 129Xe NMR spectroscopy**In memory of Professor Michael M. Pollard.

The use of three shape-persistent, conjugated macrocycles 2a–2c as ligands for self-assembly reactions is described. The macrocycles have been characterized through a combination of spectroscopic analyses and, for compounds 2b and 2c, X-ray crystallographic analysis. Whereas the reaction of 2a with the cis-Pt(II) species 3 successfully provides the porous solid 4a, the analogous reaction of 2b and 2c with 3 leads only to mixtures of products. The application of continuous-flow hyperpolarized 129Xe NMR spectroscopy to investigate the solid-state pores of macrocycles 2b and 2c and the supramolecular complex 4a as a function of temperature is described. All three species show permanent porosity upon removal of co-crystallized solvent molecules. Using trends in the 129Xe chemical shifts and temperature-dependent dynamics of Xe atoms in the solids, information is obtained on the nature of the pores in these systems. Using the 129Xe NMR data for complex 4a, the effective heat of adsorption (ΔHads) was calculated to be ~29 kJ mol–1.

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Temperature-dependent chemical shifts and isotope shifts in the NMR spectroscopy of carbon monoxide

Journal of Magnetic Resonance (1969) ◽

10.1016/0022-2364(74)90299-6 ◽

1974 ◽

Vol 14 (3) ◽

pp. 378-380 ◽

Cited By ~ 14

Author(s):

W.T Raynes ◽

G Stanney

Keyword(s):

Carbon Monoxide ◽

Nmr Spectroscopy ◽

Chemical Shifts ◽

Temperature Dependent ◽

Isotope Shifts

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Exploring Local Disorder within CAU-1 Frameworks Using Hyperpolarized 129Xe NMR Spectroscopy

Langmuir ◽

10.1021/acs.langmuir.8b02592 ◽

2018 ◽

Vol 34 (42) ◽

pp. 12538-12548 ◽

Cited By ~ 7

Author(s):

Tobias W. Kemnitzer ◽

Carsten B. L. Tschense ◽

Thomas Wittmann ◽

Ernst A. Rössler ◽

Jürgen Senker

Keyword(s):

Nmr Spectroscopy ◽

129Xe Nmr ◽

Hyperpolarized 129Xe ◽

Local Disorder

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Advanced textural characterization of biogenic silica by nitrogen physisorption, positron annihilation lifetime spectroscopy and hyperpolarized 129Xe NMR spectroscopy

Microporous and Mesoporous Materials ◽

10.1016/j.micromeso.2020.110515 ◽

2020 ◽

Vol 307 ◽

pp. 110515

Author(s):

Denise Schneider ◽

Ahmed G. Attallah ◽

Susan Wassersleben ◽

Marianne Wenzel ◽

Jörg Matysik ◽

...

Keyword(s):

Nmr Spectroscopy ◽

Positron Annihilation ◽

Biogenic Silica ◽

Positron Annihilation Lifetime Spectroscopy ◽

Positron Annihilation Lifetime ◽

129Xe Nmr ◽

Textural Characterization ◽

Hyperpolarized 129Xe

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Investigation of grafted mesoporous silicon sponge using hyperpolarized 129Xe NMR spectroscopy

Journal of Materials Research ◽

10.1557/jmr.2018.226 ◽

2018 ◽

Vol 33 (17) ◽

pp. 2637-2645 ◽

Cited By ~ 2

Author(s):

Yougang Mao ◽

Dokyoung Kim ◽

Russell Hopson ◽

Michael J. Sailor ◽

Li-Qiong Wang

Keyword(s):

Nmr Spectroscopy ◽

Mesoporous Silicon ◽

129Xe Nmr ◽

Hyperpolarized 129Xe ◽

Image Position

Abstract

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Applications of Hyperpolarized 129Xe NMR Spectroscopy to the Study of Materials

Magnetic Resonance in Colloid and Interface Science ◽

10.1007/978-94-010-0534-0_9 ◽

2002 ◽

pp. 115-122

Author(s):

I. L. Moudrakovski ◽

A. V. Nossov ◽

V. V. Terskkh ◽

S. Lang ◽

E. B. Brouwer ◽

...

Keyword(s):

Nmr Spectroscopy ◽

129Xe Nmr ◽

Hyperpolarized 129Xe

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[Leu2]Gramicidin S preserves the structural properties of its parent peptide and forms helically aligned β-sheets

Acta Crystallographica Section C Structural Chemistry ◽

10.1107/s2053229619011872 ◽

2019 ◽

Vol 75 (10) ◽

pp. 1336-1343

Author(s):

Akiko Asano ◽

Shiori Matsuoka ◽

Chisato Minami ◽

Takuma Kato ◽

Mitsinobu Doi

Keyword(s):

Structural Properties ◽

Chemical Shifts ◽

Structural Characteristics ◽

Crystallographic Analysis ◽

Coupling Constants ◽

Side Chains ◽

Gramicidin S ◽

Β Sheets ◽

Solvent Molecules ◽

Novel Scaffold

For crystallographic analysis, Leu was substituted for Orn in Gramicidin S (LGS) to suppress interactions with hydrophilic solvent molecules, which increased the flexibility of the Orn side chains, leading to disorder within the crystals. The asymmetric unit (C62H94N10O10·1.296C3H8O·1.403H2O) contains three LGS molecules (A, B and C) forming β-turn and intramolecular β-sheet structures. With the exception of one motif in molecule C, D-Phe-Pro turn motifs (Phe is phenylalanine and Pro is proline) were classed as type II′ β-turns. The peptide backbones twist slightly to the right along the long axis of the molecule. The puckering of Pro is in a Cγ-endo or twisted Cγ-endo–Cβ-exo form. Flanking molecules are arranged such that the angles (A...B = 104°, B...C = 139° and C...A = 117°) form helical β-sheets. Solvent molecules interact with the peptide backbones supporting the β-sheets. The forms of the replacement Leu side chains are consistent with the e-form of the Orn side chain in GS analogues. No hydrophilic region composed of solvent molecules, such as that observed in Gramicidin S hydrochloride (GS·HCl) crystals, was found. The perturbation of αH chemical shifts and coupling constants of CONH showed that the structural properties of GS·HCl and LGS are similar to each other in solution. CD spectra also supported the structural similarity. With the sequence cyclo(–Val–Leu–Leu–D-Phe–Pro–)2 (Val is valine and Leu is leucine), LGS lacks the amphiphilicity and antimicrobial activity of parental Gramicidin S (GS). However, the structure of LGS reflects the structural characteristics of GS and no disordering inconvenient for structural analysis was found. Thus, LGS could be a novel scaffold useful for studying β-turn and sheet structures.

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Structure of Nanobody Nb23

Molecules ◽

10.3390/molecules26123567 ◽

2021 ◽

Vol 26 (12) ◽

pp. 3567

Author(s):

Mathias Percipalle ◽

Yamanappa Hunashal ◽

Jan Steyaert ◽

Federico Fogolari ◽

Gennaro Esposito

Keyword(s):

Nmr Spectroscopy ◽

Chemical Shift ◽

Solution Structure ◽

Chemical Shifts ◽

Molecular Size ◽

Side Chain ◽

3D Nmr ◽

Target Antigen ◽

Internuclear Distances ◽

2D And 3D

Background: Nanobodies, or VHHs, are derived from heavy chain-only antibodies (hcAbs) found in camelids. They overcome some of the inherent limitations of monoclonal antibodies (mAbs) and derivatives thereof, due to their smaller molecular size and higher stability, and thus present an alternative to mAbs for therapeutic use. Two nanobodies, Nb23 and Nb24, have been shown to similarly inhibit the self-aggregation of very amyloidogenic variants of β2-microglobulin. Here, the structure of Nb23 was modeled with the Chemical-Shift (CS)-Rosetta server using chemical shift assignments from nuclear magnetic resonance (NMR) spectroscopy experiments, and used as prior knowledge in PONDEROSA restrained modeling based on experimentally assessed internuclear distances. Further validation was comparatively obtained with the results of molecular dynamics trajectories calculated from the resulting best energy-minimized Nb23 conformers. Methods: 2D and 3D NMR spectroscopy experiments were carried out to determine the assignment of the backbone and side chain hydrogen, nitrogen and carbon resonances to extract chemical shifts and interproton separations for restrained modeling. Results: The solution structure of isolated Nb23 nanobody was determined. Conclusions: The structural analysis indicated that isolated Nb23 has a dynamic CDR3 loop distributed over different orientations with respect to Nb24, which could determine differences in target antigen affinity or complex lability.

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Resolving Entangled JH-H-Coupling Patterns for Steroidal Structure Determinations by NMR Spectroscopy

Molecules ◽

10.3390/molecules26092643 ◽

2021 ◽

Vol 26 (9) ◽

pp. 2643

Author(s):

Danni Wu ◽

Kathleen Joyce Carillo ◽

Jiun-Jie Shie ◽

Steve S.-F. Yu ◽

Der-Lii M. Tzou

Keyword(s):

Nmr Spectroscopy ◽

1H Nmr Spectroscopy ◽

Chemical Shifts ◽

Atomic Level ◽

Molecular Structures ◽

Naturally Occurring ◽

Structure Determinations ◽

Ligand Interactions ◽

Synthetic Steroids ◽

The Individual

For decades, high-resolution 1H NMR spectroscopy has been routinely utilized to analyze both naturally occurring steroid hormones and synthetic steroids, which play important roles in regulating physiological functions in humans. Because the 1H signals are inevitably superimposed and entangled with various JH–H splitting patterns, such that the individual 1H chemical shift and associated JH–H coupling identities are hardly resolved. Given this, applications of thess information for elucidating steroidal molecular structures and steroid/ligand interactions at the atomic level were largely restricted. To overcome, we devoted to unraveling the entangled JH–H splitting patterns of two similar steroidal compounds having fully unsaturated protons, i.e., androstanolone and epiandrosterone (denoted as 1 and 2, respectively), in which only hydroxyl and ketone substituents attached to C3 and C17 were interchanged. Here we demonstrated that the JH–H values deduced from 1 and 2 are universal and applicable to other steroids, such as testosterone, 3β, 21-dihydroxygregna-5-en-20-one, prednisolone, and estradiol. On the other hand, the 1H chemical shifts may deviate substantially from sample to sample. In this communication, we propose a simple but novel scheme for resolving the complicate JH–H splitting patterns and 1H chemical shifts, aiming for steroidal structure determinations.

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