Advanced

Minute Additions of DMSO Affect Protein Dynamics Measurements by NMR Relaxation Experiments through Significant Changes in Solvent Viscosity

Wallerstein, Johan LU and Akke, Mikael LU (2018) In ChemPhysChem
Abstract

Studies of protein−ligand binding often rely on dissolving the ligand in dimethyl sulfoxide (DMSO) to achieve sufficient solubility, and then titrating the ligand solution into the protein solution. As a result, the final protein−ligand solution contains small amounts of DMSO in the buffer. Here we report how the addition of DMSO impacts studies of protein conformational dynamics. We used 15N NMR relaxation to compare the rotational diffusion correlation time (τC) of proteins in aqueous buffer with and without DMSO. We found that τC scales with the viscosity of the water−DMSO mixture, which depends sensitively on the amount of DMSO and varies by a factor of 2 across the relevant concentration range. NMR... (More)

Studies of protein−ligand binding often rely on dissolving the ligand in dimethyl sulfoxide (DMSO) to achieve sufficient solubility, and then titrating the ligand solution into the protein solution. As a result, the final protein−ligand solution contains small amounts of DMSO in the buffer. Here we report how the addition of DMSO impacts studies of protein conformational dynamics. We used 15N NMR relaxation to compare the rotational diffusion correlation time (τC) of proteins in aqueous buffer with and without DMSO. We found that τC scales with the viscosity of the water−DMSO mixture, which depends sensitively on the amount of DMSO and varies by a factor of 2 across the relevant concentration range. NMR relaxation studies of side chains dynamics are commonly interpreted using τC as a fixed parameter, obtained from backbone 15N relaxation data acquired on a separate sample. Model-free calculations show that errors in τC, arising from mismatched DMSO concentration between samples, lead to significant errors in order parameters. Our results highlight the importance of determining τC for each sample or carefully matching the DMSO concentrations between samples.

(Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
in press
subject
keywords
drug design, ligand binding, order parameter, rotational diffusion, side-chain dynamics
in
ChemPhysChem
publisher
John Wiley & Sons
external identifiers
  • scopus:85052942793
ISSN
1439-4235
DOI
10.1002/cphc.201800626
language
English
LU publication?
yes
id
f9fae998-91b1-42af-9070-13472fad9b50
date added to LUP
2018-10-22 13:11:19
date last changed
2019-02-20 11:32:46
@article{f9fae998-91b1-42af-9070-13472fad9b50,
  abstract     = {<p>Studies of protein−ligand binding often rely on dissolving the ligand in dimethyl sulfoxide (DMSO) to achieve sufficient solubility, and then titrating the ligand solution into the protein solution. As a result, the final protein−ligand solution contains small amounts of DMSO in the buffer. Here we report how the addition of DMSO impacts studies of protein conformational dynamics. We used <sup>15</sup>N NMR relaxation to compare the rotational diffusion correlation time (τ<sub>C</sub>) of proteins in aqueous buffer with and without DMSO. We found that τ<sub>C</sub> scales with the viscosity of the water−DMSO mixture, which depends sensitively on the amount of DMSO and varies by a factor of 2 across the relevant concentration range. NMR relaxation studies of side chains dynamics are commonly interpreted using τ<sub>C</sub> as a fixed parameter, obtained from backbone <sup>15</sup>N relaxation data acquired on a separate sample. Model-free calculations show that errors in τ<sub>C</sub>, arising from mismatched DMSO concentration between samples, lead to significant errors in order parameters. Our results highlight the importance of determining τ<sub>C</sub> for each sample or carefully matching the DMSO concentrations between samples.</p>},
  author       = {Wallerstein, Johan and Akke, Mikael},
  issn         = {1439-4235},
  keyword      = {drug design,ligand binding,order parameter,rotational diffusion,side-chain dynamics},
  language     = {eng},
  month        = {08},
  publisher    = {John Wiley & Sons},
  series       = {ChemPhysChem},
  title        = {Minute Additions of DMSO Affect Protein Dynamics Measurements by NMR Relaxation Experiments through Significant Changes in Solvent Viscosity},
  url          = {http://dx.doi.org/10.1002/cphc.201800626},
  year         = {2018},
}