Off-resonance rotating-frame amide proton spin relaxation experiments measuring microsecond chemical exchange in proteins
Lundström, Patrik LU and Akke, Mikael LU
(2005)
In Journal of Biomolecular NMR
32(2).
p.163-173
- Abstract
- NMR spin relaxation in the rotating frame (R-1 rho) is a unique method for atomic-resolution characterization of conformational ( chemical) exchange processes occurring on the microsecond time scale. Here, we use amide H-1 off-resonance R-1 rho relaxation experiments to determine exchange parameters for processes that are significantly faster than those that can be probed using N-15 or C-13 relaxation. The new pulse sequence is validated using the E140Q mutant of the C-terminal domain of calmodulin, which exhibits significant conformational exchange contributions to the transverse relaxation rates. The H-1 off-resonance R-1 rho data sample the entire relaxation dispersion profiles for the large majority of residues in this protein, which... (More)
- NMR spin relaxation in the rotating frame (R-1 rho) is a unique method for atomic-resolution characterization of conformational ( chemical) exchange processes occurring on the microsecond time scale. Here, we use amide H-1 off-resonance R-1 rho relaxation experiments to determine exchange parameters for processes that are significantly faster than those that can be probed using N-15 or C-13 relaxation. The new pulse sequence is validated using the E140Q mutant of the C-terminal domain of calmodulin, which exhibits significant conformational exchange contributions to the transverse relaxation rates. The H-1 off-resonance R-1 rho data sample the entire relaxation dispersion profiles for the large majority of residues in this protein, which exchanges between conformations with a time constant of approximately 20 mu s. This is in contrast to the case for N-15, where additional laboratory-frame relaxation data are required to determine the exchange parameters reliably. Experiments were performed on uniformly N-15-enriched samples that were either highly enriched in H-2 or fully protonated. In the latter case, dipolar cross-relaxation with aliphatic protons were effectively decoupled to first order using a selective inversion pulse. Deuterated and protonated samples gave the same results, within experimental errors. The use of deuterated samples increases the sensitivity towards exchange contributions to the H-1 transverse relaxation rates, since dipolar relaxation is greatly reduced. The exchange correlation times determined from the present H-1 off-resonance R-1 rho experiments are in excellent agreement with those determined previously using a combination of N-15 laboratory-frame and off-resonance R-1 rho relaxation data, with average values of <tau(ex)> = 19 +/- 7 and 21 +/- 3 mu s, respectively. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/151504
- author
- Lundström, Patrik
LU
and Akke, Mikael
LU
- organization
- publishing date
- 2005
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Journal of Biomolecular NMR
- volume
- 32
- issue
- 2
- pages
- 163 - 173
- publisher
- Springer
- external identifiers
-
- pmid:16034667
- wos:000230694100006
- scopus:23344439330
- ISSN
- 1573-5001
- DOI
- 10.1007/s10858-005-5027-3
- language
- English
- LU publication?
- yes
- id
- 69c2f928-2f2a-4bd1-af31-30cdbf7e4b8e (old id 151504)
- date added to LUP
- 2016-04-01 11:57:10
- date last changed
- 2022-01-26 20:38:27
@article{69c2f928-2f2a-4bd1-af31-30cdbf7e4b8e,
abstract = {{NMR spin relaxation in the rotating frame (R-1 rho) is a unique method for atomic-resolution characterization of conformational ( chemical) exchange processes occurring on the microsecond time scale. Here, we use amide H-1 off-resonance R-1 rho relaxation experiments to determine exchange parameters for processes that are significantly faster than those that can be probed using N-15 or C-13 relaxation. The new pulse sequence is validated using the E140Q mutant of the C-terminal domain of calmodulin, which exhibits significant conformational exchange contributions to the transverse relaxation rates. The H-1 off-resonance R-1 rho data sample the entire relaxation dispersion profiles for the large majority of residues in this protein, which exchanges between conformations with a time constant of approximately 20 mu s. This is in contrast to the case for N-15, where additional laboratory-frame relaxation data are required to determine the exchange parameters reliably. Experiments were performed on uniformly N-15-enriched samples that were either highly enriched in H-2 or fully protonated. In the latter case, dipolar cross-relaxation with aliphatic protons were effectively decoupled to first order using a selective inversion pulse. Deuterated and protonated samples gave the same results, within experimental errors. The use of deuterated samples increases the sensitivity towards exchange contributions to the H-1 transverse relaxation rates, since dipolar relaxation is greatly reduced. The exchange correlation times determined from the present H-1 off-resonance R-1 rho experiments are in excellent agreement with those determined previously using a combination of N-15 laboratory-frame and off-resonance R-1 rho relaxation data, with average values of <tau(ex)> = 19 +/- 7 and 21 +/- 3 mu s, respectively.}},
author = {{Lundström, Patrik and Akke, Mikael}},
issn = {{1573-5001}},
language = {{eng}},
number = {{2}},
pages = {{163--173}},
publisher = {{Springer}},
series = {{Journal of Biomolecular NMR}},
title = {{Off-resonance rotating-frame amide proton spin relaxation experiments measuring microsecond chemical exchange in proteins}},
url = {{http://dx.doi.org/10.1007/s10858-005-5027-3}},
doi = {{10.1007/s10858-005-5027-3}},
volume = {{32}},
year = {{2005}},
}