Design of small volume HX and triple-resonance probes for improved limits of detection in protein NMR experiments.
Three- and four-frequency nuclear magnetic-resonance probes have been designed for the study of small amounts of protein. Both "HX" (1H, X, and 2H channels) and "triple-resonance" (1H, 15N, 13C, and 2H) probes were implemented using a single transmit/receive coil and multiple-frequency impedance matching circuits. The coil used was a six-turn solenoid with an observe volume of 15 microl. A variable pitch design was used to improve the B1 homogeneity of the coil. Two-dimensional HSQC spectra of approximately 1mM single labeled 15N- and double labeled 15N/13C-proteins were acquired in experimental times of approximately 2h. Triple-resonance capability of the small-volume triple-resonance probe was demonstrated by acquiring three-dimensional HNCO spectra from the same protein samples. In addition to enabling very small quantities of protein to be used, the extremely short pulse widths (1H = 4, 15N = 4, and 13C = 2 micros) of this particular design result in low power decoupling and wide-bandwidth coverage, an important factor for the ever-higher operating frequencies used for protein NMR studies.
Li
Yu
Y
Department of Electrical and Computer Engineering and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
Logan
Timothy M
TM
Edison
Arthur S
AS
Webb
Andrew
A
D002247:Carbon Isotopes; D004867:Equipment Design; D008154:Lucanthone / Q000031:analogs & derivatives* / Q000737:chemistry; D008280:Magnetics / Q000295:instrumentation*; D008832:Microchemistry / Q000295:instrumentation* / Q000379:methods; D009587:Nitrogen Isotopes; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000295:instrumentation* / Q000379:methods; D011506:Proteins / Q000737:chemistry*; D011522:Protons; D011786:Quality Control; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014159:Transducers; D025801:Ubiquitin / Q000737:chemistry
D002247:Carbon Isotopes; D009587:Nitrogen Isotopes; D011506:Proteins; D011522:Protons; D025801:Ubiquitin; C006009:IA 3; D008154:Lucanthone