Design of small volume HX and triple-resonance probes for improved limits of detection in protein NMR experiments

• Published in: Journal of magnetic resonance (1997) Vol. 164; no. 1; pp. 128 - 135
• Main Authors: Li, Yu, Logan, Timothy M, Edison, Arthur S, Webb, Andrew
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.09.2003
• Subjects: Carbon Isotopes; Equipment Design; Lucanthone - analogs & derivatives; Lucanthone - chemistry; Magnetics - instrumentation; Microchemistry - instrumentation; Microchemistry - methods; Nitrogen Isotopes; Nuclear Magnetic Resonance, Biomolecular - instrumentation; Nuclear Magnetic Resonance, Biomolecular - methods; Proteins - chemistry; Protons; Quality Control; Reproducibility of Results; Sensitivity and Specificity; solenoids; Transducers; Ubiquitin - chemistry
• ISSN: 1090-7807; 1096-0856
• DOI: 10.1016/S1090-7807(03)00184-8

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 μl. A variable pitch design was used to improve the B 1 homogeneity of the coil. Two-dimensional HSQC spectra of ∼1 mM single labeled 15N- and double labeled 15N/ 13C-proteins were acquired in experimental times of approximately 2 h. 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 μs) 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.