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Monitoring 15N Chemical Shifts During Protein Folding by Pressure-Jump NMR.

ABSTRACT: Pressure-jump hardware permits direct observation of protein NMR spectra during a cyclically repeated protein folding process. For a two-state folding protein, the change in resonance frequency will occur nearly instantaneously when the protein clears the transition state barrier, resulting in a monoexponential change of the ensemble-averaged chemical shift. However, protein folding pathways can be more complex and contain metastable intermediates. With a pseudo-3D NMR experiment that utilizes stroboscopic observation, we measure the ensemble-averaged chemical shifts, including those of exchange-broadened intermediates, during the folding process. Such measurements for a pressure-sensitized mutant of ubiquitin show an on-pathway kinetic intermediate whose 15N chemical shifts differ most from the natively folded protein for strands ?5, its preceding turn, and the two strands that pair with ?5 in the native structure.

SUBMITTER: Charlier C

PROVIDER: S-EPMC6119464 | biostudies-literature | 2018 Jul

REPOSITORIES: biostudies-literature

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Monitoring 15N Chemical Shifts During Protein Folding by Pressure-Jump NMR.

Charlier Cyril C Courtney Joseph M JM Alderson T Reid TR Anfinrud Philip P Bax Ad A

Journal of the American Chemical Society 20180625 26

Pressure-jump hardware permits direct observation of protein NMR spectra during a cyclically repeated protein folding process. For a two-state folding protein, the change in resonance frequency will occur nearly instantaneously when the protein clears the transition state barrier, resulting in a monoexponential change of the ensemble-averaged chemical shift. However, protein folding pathways can be more complex and contain metastable intermediates. With a pseudo-3D NMR experiment that utilizes s ...[more]

PMID: 29923716

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