Magic angle spinning 13C-NMR spin-lattice relaxation study of the location and effects of ?-tocopherol, ubiquinone-10 and ubiquinol-10 in unsonicated model membranes

1993 ◽  
Vol 22 (2) ◽  
Author(s):  
Josefa Salgado ◽  
Jose Villalain ◽  
JuanC. G�mez-Fern�ndez
Author(s):  
ASIF EQUBAL ◽  
Kan Tagami ◽  
Songi Han

In this paper, we report on an entirely novel way of improving the MAS-DNP efficiency by shaped μw pulse train irradiation for fast and broad-banded (FAB) saturation of the electron spin resonance. FAB-DNP achieved with Arbitrary Wave Generated shaped μw pulse trains facilitates effective and selective saturation of a defined fraction of the total electron spins, and provides superior control over the DNP efficiency under MAS. Experimental and quantum-mechanics based numerically simulated results together demonstrate that FAB-DNP significantly outperforms CW-DNP when the EPR-line of PAs is broadened by conformational distribution and exchange coupling. We demonstrate that the maximum benefit of FAB DNP is achieved when the electron spin-lattice relaxation is fast relative to the MAS frequency, i.e. at higher temperatures and/or when employing metals as PAs. Calculations predict that under short T<sub>1e </sub>conditions AWG-DNP can achieve as much as ~4-fold greater enhancement compared to CW-DNP.


2011 ◽  
Vol 212 (2) ◽  
pp. 460-463 ◽  
Author(s):  
Riddhiman Sarkar ◽  
Maria Concistrè ◽  
Ole G. Johannessen ◽  
Peter Beckett ◽  
Mark Denning ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document