Practical considerations for investigation of protein conformational dynamics by 15N R 1ρ relaxation dispersion.
J Biomol NMR
; 67(3): 201-209, 2017 03.
Article
em En
| MEDLINE
| ID: mdl-28243767
ABSTRACT
It is becoming increasingly apparent that proteins are not static entities and that their function often critically depends on accurate sampling of multiple conformational states in aqueous solution. Accordingly, the development of methods to study conformational states in proteins beyond their ground-state structure ("excited states") has crucial biophysical importance. Here we investigate experimental schemes for optimally probing chemical exchange processes in proteins on the micro- to millisecond timescale by 15N R 1ρ relaxation dispersion. The schemes use selective Hartmann-Hahn cross-polarization (CP) transfer for excitation, and derive peak integrals from 1D NMR spectra (Korzhnev et al. in J Am Chem Soc 127713-721, 2005; Hansen et al. in J Am Chem Soc 1313818-3819, 2009). Simulation and experiment collectively show that in such CP-based schemes care has to be taken to achieve accurate suppression of undesired off-resonance coherences, when using weak spin-lock fields. This then (i) ensures that relaxation dispersion profiles in the absence of chemical exchange are flat, and (ii) facilitates extraction of relaxation dispersion profiles in crowded regions of the spectrum. Further improvement in the quality of the experimental data is achieved by recording the free-induction decays in an interleaved manner and including a heating-compensation element. The reported considerations will particularly benefit the use of CP-based R 1ρ relaxation dispersion to analyze conformational exchange processes in larger proteins, where resonance line overlap becomes the main limiting factor.
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Conformação Proteica
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Espectroscopia de Ressonância Magnética
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Proteínas
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Ressonância Magnética Nuclear Biomolecular
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Simulação de Dinâmica Molecular
Idioma:
En
Revista:
J Biomol NMR
Assunto da revista:
BIOLOGIA MOLECULAR
/
DIAGNOSTICO POR IMAGEM
/
MEDICINA NUCLEAR
Ano de publicação:
2017
Tipo de documento:
Article
País de afiliação:
Japão