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[NMR paper] Mixed Fluorotryptophan Substitutions at the Same Residue Expand the Versatility of ¹?F Protein NMR Spectroscopy.
Jan 18, 2018 - 12:41 PM - by nmrlearner
nmrlearner's Avatar Mixed Fluorotryptophan Substitutions at the Same Residue Expand the Versatility of ¹?F Protein NMR Spectroscopy.

Mixed Fluorotryptophan Substitutions at the Same Residue Expand the Versatility of ¹?F Protein NMR Spectroscopy.

Chemistry. 2018 Jan 17;:

Authors: Kenward C, Shin K, Rainey J

Abstract
The strategy of applying fluorine NMR to characterize ligand binding to a membrane protein prepared with mixtures of tryptophans substituted with F at different positions on the indole ring was tested. The ¹?F NMR behavior of 4-, 5-, 6-, and 7-fluorotryptophan were directly compared as a function of both micellar environment and fragment size for two overlapping apelin receptor (AR/APJ) segments - one with a single transmembrane (TM) helix and two tryptophan residues, the other with three TM helices and two additional tryptophan residues. Chemical shifts, peak patterns, and nuclear spin relaxation rates were observed to vary as a function of micellar conditions and F substitution position in the indole ring, with the exposure of a given residue to micelle or solvent being the primary differentiating factor. Titration of the 3-TM AR segment biosynthetically prepared with mixtures of 5- and 7-fluorotryptophan by two distinct peptide ligands - apelin-36 and apela-32 - demonstrated site-specific ¹?F peak intensity changes for one ligand but not the other. In contrast, both ligands perturbed ¹H-¹?N heteronuclear single quantum coherence experiment peak patterns to a similar degree. Characterization of fluorotryptophan mixtures for a given set of tryptophan residues, thus, significantly augments the potential to apply ¹?F NMR to track otherwise obscure... [Read More]
0 Replies | 2 Views
[NMR paper] Direct Detection of Carbon and Nitrogen Nuclei for High-Resolution Analysis of Intrinsically Disordered Proteins using NMR Spectroscopy.
Jan 18, 2018 - 12:41 PM - by nmrlearner
nmrlearner's Avatar Direct Detection of Carbon and Nitrogen Nuclei for High-Resolution Analysis of Intrinsically Disordered Proteins using NMR Spectroscopy.

Direct Detection of Carbon and Nitrogen Nuclei for High-Resolution Analysis of Intrinsically Disordered Proteins using NMR Spectroscopy.

Methods. 2018 Jan 13;:

Authors: Gibbs EB, Kriwacki RW

Abstract
Nuclear magnetic resonance spectroscopy (NMR) is a powerful technique for characterizing the structural and dynamic properties of intrinsically disordered proteins and protein regions (IDPs & IDRs). However, the application of NMR to IDPs has been limited by poor chemical shift dispersion in two-dimensional (2D) 1H-15N heteronuclear correlation spectra. Among the various detection schemes available for heteronuclear correlation spectroscopy, 13C direct-detection has become a mainstay for investigations of IDPs owing to the favorable chemical shift dispersion in 2D 13C'-15N correlation spectra. Recent advances in cryoprobe technology have enhanced the sensitivity for direct detection of both 13C and 15N resonances at high magnetic field strengths, thus prompting the development of 15N direct-detect experiments to complement established 13C-detection experiments. However, the application of 15N-detection has not been widely explored for IDPs. Here we compare 1H, 13C, and 15N detection schemes for a variety of 2D heteronuclear correlation spectra and evaluate their performance on the basis of resolution, chemical shift dispersion, and sensitivity. We performed experiments with a variety of disordered systems ranging in size and complexity; from a small IDR (99 amino acids), to a large low complexity IDR (185... [Read More]
0 Replies | 3 Views
[NMR paper] The influence of fatty acids on metoprolol - human serum albumin interaction in low affinity binding sites: a multifactorial NMR approach.
Jan 18, 2018 - 12:41 PM - by nmrlearner
nmrlearner's Avatar The influence of fatty acids on metoprolol - human serum albumin interaction in low affinity binding sites: a multifactorial NMR approach.

Related Articles The influence of fatty acids on metoprolol - human serum albumin interaction in low affinity binding sites: a multifactorial NMR approach.

Protein Pept Lett. 2018 Jan 15;:

Authors: Szkudlarek A, Mogielnicki M, Pentak D, Ploch A, Maciazek-Jurczyk M

Abstract
The aim of the study was to evaluate the mechanism of interaction between metoprolol (MTP) and human serum albumin (HSA) using 1H NMR technique. The analysis of the drug-albumin interaction was based on the observed chemical shifts in combination with correlation times, 2D NOESY 1H NMR spectra and association constants and allowed us to observe the interactions between the aromatic rings of the drug and the amino acids of the protein. The binding of the drug, both in the hydrophobic subdomain and on the surface of the albumin, increases in the presence of fatty acids (FAs).


PMID: 29336242 [PubMed - as supplied by publisher]



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0 Replies | 3 Views
[NMR paper] Phosphorylation-induced conformation of ?2-adrenoceptor related to arrestin recruitment revealed by NMR.
Jan 18, 2018 - 12:41 PM - by nmrlearner
nmrlearner's Avatar Phosphorylation-induced conformation of ?2-adrenoceptor related to arrestin recruitment revealed by NMR.

Related Articles Phosphorylation-induced conformation of ?2-adrenoceptor related to arrestin recruitment revealed by NMR.

Nat Commun. 2018 Jan 15;9(1):194

Authors: Shiraishi Y, Natsume M, Kofuku Y, Imai S, Nakata K, Mizukoshi T, Ueda T, Iwaï H, Shimada I

Abstract
The C-terminal region of G-protein-coupled receptors (GPCRs), stimulated by agonist binding, is phosphorylated by GPCR kinases, and the phosphorylated GPCRs bind to arrestin, leading to the cellular responses. To understand the mechanism underlying the formation of the phosphorylated GPCR-arrestin complex, we performed NMR analyses of the phosphorylated ?2-adrenoceptor (?2AR) and the phosphorylated ?2AR-?-arrestin 1 complex, in the lipid bilayers of nanodisc. Here we show that the phosphorylated C-terminal region adheres to either the intracellular side of the transmembrane region or lipids, and that the phosphorylation of the C-terminal region allosterically alters the conformation around M2155.54 and M2796.41, located on transemembrane helices 5 and 6, respectively. In addition, we found that the conformation induced by the phosphorylation is similar to that corresponding to the ?-arrestin-bound state. The phosphorylation-induced structures revealed in this study propose a conserved structural motif of GPCRs that enables... [Read More]
0 Replies | 3 Views
Direct Detection of Carbon and Nitrogen Nuclei for High-Resolution Analysis of Intrinsically Disordered Proteins using NMR Spectroscopy
Jan 17, 2018 - 7:00 PM - by nmrlearner
nmrlearner's Avatar Direct Detection of Carbon and Nitrogen Nuclei for High-Resolution Analysis of Intrinsically Disordered Proteins using NMR Spectroscopy

Publication date: Available online 16 January 2018
Source:Methods

Author(s): E.B. Gibbs, R.W. Kriwacki

Nuclear magnetic resonance spectroscopy (NMR) is a powerful technique for characterizing the structural and dynamic properties of intrinsically disordered proteins and protein regions (IDPs & IDRs). However, the application of NMR to IDPs has been limited by poor chemical shift dispersion in two-dimensional (2D) 1H-15N heteronuclear correlation spectra. Among the various detection schemes available for heteronuclear correlation spectroscopy, 13C direct-detection has become a mainstay for investigations of IDPs owing to the favorable chemical shift dispersion in 2D 13C?-15N correlation spectra. Recent advances in cryoprobe technology have enhanced the sensitivity for direct detection of both 13C and 15N resonances at high magnetic field strengths, thus prompting the development of 15N direct-detect experiments to complement established 13C-detection experiments. However, the application of 15N-detection has not been widely explored for IDPs. Here we compare 1H, 13C, and 15N detection schemes for a variety of 2D heteronuclear correlation spectra and evaluate their performance on the basis of resolution, chemical shift dispersion, and sensitivity. We performed experiments with a variety of disordered... [Read More]
0 Replies | 9 Views
Magic angle spinning NMR below 6 K with a computational fluid dynamics analysis of fluid flow and temperature gradients
Jan 17, 2018 - 7:00 PM - by nmrlearner
nmrlearner's Avatar From The DNP-NMR Blog:

Magic angle spinning NMR below 6 K with a computational fluid dynamics analysis of fluid flow and temperature gradients

This article is not specifically about DNP spectroscopy. However, magic angle spinning at 6K is definitely of interest to DNP, especially when using low-power, solid-state microwave sources.




Sesti, E.L., et al., Magic angle spinning NMR below 6 K with a computational fluid dynamics analysis of fluid flow and temperature gradients. J. Magn. Reson., 2018. 286(Supplement C): p. 1-9.


http://www.sciencedirect.com/science...90780717302689


We report magic angle spinning (MAS) up to 8.5 kHz with a sample temperature below 6 K using liquid helium as a variable temperature fluid. Cross polarization 13C NMR spectra exhibit exquisite sensitivity with a single transient. Remarkably, 1H saturation recovery experiments show a 1H T1 of 21 s with MAS below 6 K in the presence of trityl radicals in a glassy matrix. Leveraging the thermal spin polarization available at 4.2 K versus 298 K should result in 71 times higher signal intensity. Taking the 1H longitudinal relaxation into account, signal averaging times are therefore predicted to be expedited by a factor of >500. Computer assisted design (CAD) and finite element analysis were employed in both the design and diagnostic stages of this cryogenic MAS technology development. Computational fluid dynamics (CFD) models describing temperature gradients and fluid flow are presented. The CFD models bearing and drive gas maintained at 100 K, while a... [Read More]
0 Replies | 7 Views
Using Chemical Synthesis To Study and Apply Protein Glycosylation
Jan 17, 2018 - 5:28 AM - by nmrlearner
nmrlearner's Avatar Using Chemical Synthesis To Study and Apply Protein Glycosylation



Biochemistry
DOI: 10.1021/acs.biochem.7b01055



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0 Replies | 9 Views
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