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Proton-Assisted Recoupling (PAR) in Peptides and Proteins

Donovan, Kevin J.; Jain, Sheetal K.; Silvers, Robert; Linse, Sara LU and Griffin, Robert G. (2017) In Journal of Physical Chemistry B 121(48). p.10804-10817
Abstract

Proton-assisted recoupling (PAR) is examined by exploring optimal experimental conditions and magnetization transfer rates in a variety of biologically relevant nuclear spin-systems, including simple amino acids, model peptides, and two proteins-nanocrystalline protein G (GB1), and importantly amyloid beta 1-42 (M01-42) fibrils. A selective PAR protocol, SUBPAR (setting up better proton assisted recoupling), is described to observe magnetization transfer in one-dimensional spectra, which minimizes experiment time (in comparison to two-dimensional experiments) and thereby enables an efficient assessment of optimal PAR conditions for a desired magnetization transfer. In the case of the peptide spin systems,... (More)

Proton-assisted recoupling (PAR) is examined by exploring optimal experimental conditions and magnetization transfer rates in a variety of biologically relevant nuclear spin-systems, including simple amino acids, model peptides, and two proteins-nanocrystalline protein G (GB1), and importantly amyloid beta 1-42 (M01-42) fibrils. A selective PAR protocol, SUBPAR (setting up better proton assisted recoupling), is described to observe magnetization transfer in one-dimensional spectra, which minimizes experiment time (in comparison to two-dimensional experiments) and thereby enables an efficient assessment of optimal PAR conditions for a desired magnetization transfer. In the case of the peptide spin systems, experimental and simulated PAR data sets are compared on a semiquantitative level, thereby elucidating the interactions influencing PAR magnetization transfer and their manifestations in different spin transfer networks. Using the optimum Rabi frequencies determined by SUBPAR, PAR magnetization transfer trajectories (or buildup curves) were recorded and compared to simulated results for short peptides. PAR buildup curves were also recorded for M01-42 and examined conjointly with a recent structural model. The majority of salient cross-peak intensities observed in the M01-42 PAR spectra are well-modeled with a simple biexponential equation, although the fitting parameters do not show any strong correlation to internuclear distances. Nevertheless, these parameters provide a wealth of invaluable semiquantitative structural constraints for the M01-42. The results presented here offer a complete protocol for recording PAR 13C-13C correlation spectra with high-efficiency and using the resulting information in protein structural studies.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Physical Chemistry B
volume
121
issue
48
pages
14 pages
publisher
The American Chemical Society
external identifiers
  • scopus:85037740541
  • wos:000417672200008
ISSN
1520-6106
DOI
10.1021/acs.jpcb.7b08934
language
English
LU publication?
yes
id
f545bc6c-c4ed-4db9-a769-413c0f7e2b41
date added to LUP
2018-01-03 13:17:11
date last changed
2018-01-16 13:28:54
@article{f545bc6c-c4ed-4db9-a769-413c0f7e2b41,
  abstract     = {<p>Proton-assisted recoupling (PAR) is examined by exploring optimal experimental conditions and magnetization transfer rates in a variety of biologically relevant nuclear spin-systems, including simple amino acids, model peptides, and two proteins-nanocrystalline protein G (GB1), and importantly amyloid beta 1-42 (M<sub>0</sub>Aβ<sub>1-42</sub>) fibrils. A selective PAR protocol, SUBPAR (setting up better proton assisted recoupling), is described to observe magnetization transfer in one-dimensional spectra, which minimizes experiment time (in comparison to two-dimensional experiments) and thereby enables an efficient assessment of optimal PAR conditions for a desired magnetization transfer. In the case of the peptide spin systems, experimental and simulated PAR data sets are compared on a semiquantitative level, thereby elucidating the interactions influencing PAR magnetization transfer and their manifestations in different spin transfer networks. Using the optimum Rabi frequencies determined by SUBPAR, PAR magnetization transfer trajectories (or buildup curves) were recorded and compared to simulated results for short peptides. PAR buildup curves were also recorded for M<sub>0</sub>Aβ<sub>1-42</sub> and examined conjointly with a recent structural model. The majority of salient cross-peak intensities observed in the M<sub>0</sub>Aβ<sub>1-42</sub> PAR spectra are well-modeled with a simple biexponential equation, although the fitting parameters do not show any strong correlation to internuclear distances. Nevertheless, these parameters provide a wealth of invaluable semiquantitative structural constraints for the M<sub>0</sub>Aβ<sub>1-42</sub>. The results presented here offer a complete protocol for recording PAR <sup>13</sup>C-<sup>13</sup>C correlation spectra with high-efficiency and using the resulting information in protein structural studies.</p>},
  author       = {Donovan, Kevin J. and Jain, Sheetal K. and Silvers, Robert and Linse, Sara and Griffin, Robert G.},
  issn         = {1520-6106},
  language     = {eng},
  month        = {12},
  number       = {48},
  pages        = {10804--10817},
  publisher    = {The American Chemical Society},
  series       = {Journal of Physical Chemistry B},
  title        = {Proton-Assisted Recoupling (PAR) in Peptides and Proteins},
  url          = {http://dx.doi.org/10.1021/acs.jpcb.7b08934},
  volume       = {121},
  year         = {2017},
}