Interrupted Pressure-Jump NMR Experiments Reveal Resonances of On-Pathway Protein Folding Intermediate
| Autor: | Joseph M. Courtney, Cyril Charlier, Ad Bax, Philip A. Anfinrud |
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| Rok vydání: | 2018 |
| Předmět: |
0301 basic medicine
On pathway Protein Folding Double mutant Chemistry Chemical shift Proteins 010402 general chemistry Pressure jump 01 natural sciences Article Protein Structure Secondary 0104 chemical sciences Surfaces Coatings and Films Folding (chemistry) 03 medical and health sciences 030104 developmental biology Protein structure Chemical physics High pressure Pressure Materials Chemistry Protein folding Physical and Theoretical Chemistry Nuclear Magnetic Resonance Biomolecular |
| Zdroj: | The Journal of Physical Chemistry B. 122:11792-11799 |
| ISSN: | 1520-5207 1520-6106 |
| Popis: | Previous pressure-jump NMR experiments on a pressure-sensitized double mutant of ubiquitin showed evidence that its folding occurs via two parallel, comparably efficient pathways: A single barrier and a two-barrier pathway. An interrupted folding NMR experiment is introduced, where for a brief period the pressure is dropped to atmospheric conditions (1 bar), followed by a jump back to high pressure for signal detection. Conventional, forward sampling of the indirect dimension during the low-pressure period correlates the (15)N or (13)C′ chemical shifts of the unfolded protein at 1 bar to the (1)H frequencies of both the unfolded and folded proteins at high pressure. Remarkably, sampling the data of the same experiment in the reverse direction yields the frequencies of proteins present at the end of the low-pressure interval, which include unfolded, intermediate, and folded species. Although the folding intermediate (15)N shifts differ strongly from natively folded protein, its (13)C′ chemical shifts, which are more sensitive probes for secondary structure, closely match those of the folded protein and indicate that the folding intermediate must have a structure that is quite similar to the native state. |
| Databáze: | OpenAIRE |
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