Biomedical subjects

Zhehong Gan

Publications and source records attributed to Zhehong Gan.

4 recordsLinked to original sources

PubMed2003

Direct detection of potassium cations bound to G-quadruplex structures by solid-state 39K NMR at 19.6 T.

We report solid-state 39K NMR detection of the K+ ions bound to three G-quadruplex structures formed by self-assembly of 5'-tert-butyl-dimethylsilyl-2',3'-O-isopropylidene guanosine, guanosine, and guanosine 5'-monophosphate. The 39K NMR spectra clearly show different spectral signatures for K+ ions inside the G-quadruplex channel and for K+ ions bound to the phosphate groups. Solid-state 39K NMR spectra for hydrated K salts of adenosine 2'-monophosphate and adenosine 5'-diphosphate are also reported.

Cations, Monovalent↗

PubMed2003

Double-quantum filtered STMAS.

Double-quantum and double-quantum-filtered satellite-transition magic-angle spinning (STMAS) experiments are proposed. The experiments efficiently convert satellite-transition coherence from single- to double-quantum with a central-transition selective pi-pulse. The conversion allows the selection of double-quantum coherence transfer pathways with phase cycling that completely filters out unwanted diagonal and outer satellite-transition peaks. Both experiments are demonstrated with RbNO3 and AlPO4-berlinite as model compounds for obtaining clean STMAS spectra of spins 3/2 and 5/2, respectively.

Journal Article↗

PubMed2002

Seeking higher resolution and sensitivity for NMR of quadrupolar nuclei at ultrahigh magnetic fields.

We report the acquisition of solid-state NMR spectra of quadrupolar nuclei obtained at very high magnetic fields (25 and 40 T), thus improving spectral sensitivity and resolution. For an example compound, the MAS spectrum obtained at 40 T is nearly free from the second-order quadrupolar broadening and can be interpreted quantitatively in a very simple manner.

Journal Article↗

PubMed2002

Optimizing STMAS.

The 2D satellite transition magic angle spinning (STMAS) experiment generates efficiently high-resolution isotropic NMR spectra of half-integer quadrupolar nuclei. The experiment involves excitation and coherence transfer of satellite transitions into the central transition. It requires efficient refocusing of satellite transitions and sample spinning at a very accurate magic angle to cancel the first-order quadrupolar interaction effect. A review of all parameters relevant to optimizing the STMAS experiment is presented, including pulse sequence calibration, regulating spinning speed, magic angle adjustment, optimization of satellite transition excitation, and coherence transfer for both I = 3/2 and I > or =5/2 nuclei.

Calibration↗