Reduction of RF-induced sample heating with a scroll coil resonator structure for solid-state NMR probes.
Heating due to high power 1H decoupling limits the experimental lifetime of protein samples for solid-state NMR (SSNMR). Sample deterioration can be minimized by lowering the experimental salt concentration, temperature or decoupling fields; however, these approaches may compromise biological relevance and/or spectroscopic resolution and sensitivity. The desire to apply sophisticated multiple pulse experiments to proteins therefore motivates the development of probes that utilize the RF power more efficiently to generate a high ratio of magnetic to electric field in the sample. Here a novel scroll coil resonator structure is presented and compared to a traditional solenoid. The scroll coil is demonstrated to be more tolerant of high sample salt concentrations and cause less RF-induced sample heating. With it, the viable experimental lifetime of a microcrystalline ubiquitin sample has been extended by more than an order of magnitude. The higher B1 homogeneity and permissible decoupling fields enhance polarization transfer efficiency in 15N-13C correlation experiments employed for protein chemical shift assignments and structure determination.
Stringer
John A
JA
Varian, Inc., 2607 Midpoint Drive, Fort Collins, CO 80525, USA.
Bronnimann
Charles E
CE
Mullen
Charles G
CG
Zhou
Donghua H
DH
Stellfox
Sara A
SA
Li
Ying
Y
Williams
Evan H
EH
Rienstra
Chad M
CM
D002247:Carbon Isotopes; D004867:Equipment Design; D006358:Hot Temperature; D009587:Nitrogen Isotopes; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000295:instrumentation*; D009942:Organometallic Compounds; D009943:Organophosphorus Compounds; D011506:Proteins / Q000737:chemistry*; D011846:Radio Waves; D012680:Sensitivity and Specificity; D012965:Sodium Chloride; D014159:Transducers
D002247:Carbon Isotopes; D009587:Nitrogen Isotopes; D009942:Organometallic Compounds; D009943:Organophosphorus Compounds; D011506:Proteins; C069929:thulium(III) 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetramethylenephosphonate; D012965:Sodium Chloride