Characterizing Slow Chemical Exchange in Nucleic Acids by Carbon CEST and Low Spin-Lock FieldR1ρNMR Spectroscopy

Extending the range of microsecond-to-millisecond chemical exchange detected in labeled and unlabeled nucleic acids by selective carbon R(1rho) NMR spectroscopy.

We present an off-resonance carbon R(1rho) NMR experiment utilizing weak radiofrequency fields and selective polarization transfers for quantifying chemical-exchange processes in nucleic acids. The experiment extends the range of accessible time scales to approximately 10 ms, and its time-saving feature makes it possible to thoroughly map out dispersion profiles and conduct measurements at natu...

Study of chemical exchange in the intermediate exchange regime: a comparison of spin-locking and CEST techniques

Introduction: Recently, an indirect MRI detection of hydroxyl protons of small metabolites via the water signal was reported [1]. Selective off-resonance irradiation attenuates the water signal via chemical exchange saturation transfer (CEST) between hydroxyl and water protons. It was found that the magnetisation transfer (MT) asymmetry ratio (MTRasym) depends nonlinearly on hydroxyl-group conc...

Chemical Specificity of Nucleic Acids and Mechanism

Analytical determination of the chemical exchange saturation transfer (CEST) contrast in molecular magnetic resonance imaging

Magnetic resonance based on molecular imaging allows tracing contrast agents thereby facilitating early diagnosis of diseases in a non-invasive fashion that enhances the soft tissue with high spatial resolution. Recently, the exchange of protons between the contrast agent and water, known as the chemical exchange saturation transfer (CEST) effect, has been measured by applying a suitable pulse ...

Chemical exchange saturation transfer (CEST) and MR Z-spectroscopy in vivo: a review of theoretical approaches and methods.

Chemical exchange saturation transfer (CEST) of metabolite protons that undergo exchange processes with the abundant water pool enables a specific contrast for magnetic resonance imaging (MRI). The CEST image contrast depends on physical and physiological parameters that characterize the microenvironment such as temperature, pH, and metabolite concentration. However, CEST imaging in vivo is a c...