These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Practical aspects of high-sensitivity multidimensional ¹³C MAS NMR spectroscopy of perdeuterated proteins.
    Author: Akbey U, Rossum BJ, Oschkinat H.
    Journal: J Magn Reson; 2012 Apr; 217():77-85. PubMed ID: 22440428.
    Abstract:
    The double nucleus enhanced recoupling (DONER) experiment employs simultaneous irradiation of protons and deuterons to promote spin diffusion processes in a perdeuterated protein. This results in 4-5 times higher sensitivity in 2D (13)C-(13)C correlation experiments as compared to PDSD [1]. Here, a quantitative comparison of PDSD, (1)H-DARR, (2)H-DARR, and (1)H+(2)H DONER has been performed to analyze the influence of spin diffusion on polarization transfer processes. Cross peak buildup curves were analyzed to obtain guidelines for choosing the best experimental parameters. The largest cross peak intensities were observed for the DONER experiments. The fastest build-up rate was observed in the (2)H-DARR experiment within a buildup range of ∼18-45 ms, whereas values between 24 and 69 ms are observed for the DONER experiment. Furthermore, the effects of direct excitation and cross polarization (CP) are compared. A comparison between DONER and RFDR experiments reveal ∼50% more intense cross peaks in the C(α)-CO and C(α)-C(alip) regions of the 2D (13)C-(13)C DONER spectrum applying proton CP ((1)H-(13)C). As a parameter determining the S/N in (13)C-(13)C correlation experiments, proton CP efficiency is investigated using deuterated samples with proton/deuterium ratios at 20%, 40%, and 100% H(2)O. Sufficiently strong (13)C CPMAS signal intensity is observed for such proteins even with very low proton concentration. The effect of proton and/or deuterium decoupling is analyzed at various MAS spinning frequencies. Deuterium decoupling was found most crucial for obtaining high resolution. Long range correlations are readily observed representing distances up to ∼6 Å by using DONER approach.
    [Abstract] [Full Text] [Related] [New Search]