Fast magic angle spinning for the characterization of milligram quantities of organic and biological solids at natural isotopic abundance by 13C-13C correlation DNP-enhanced NMR

We show that multidimensional solid-state NMR 13C-13C correlation spectra of biomolecular assemblies and microcrystalline organic molecules can be acquired at natural isotopic abundance with only milligram quantities of sample. These experiments combine fast Magic Angle Spinning of the sample, low-power dipolar recoupling, and dynamic nuclear polarization performed with AsymPol biradicals, a recently introduced family of polarizing agents. Such experiments are essential for structural characterization as they provide short-and long-range distance information. This approach is demonstrated on diverse sample types, including polyglutamine fibrils implicated in Huntington's disease and microcrystalline ampicillin, a small antibiotic molecule.

Automated summary

We demonstrate a technique for acquiring multidimensional solid-state NMR 13C-13C correlation spectra of biomolecular assemblies and microcrystalline organic molecules at natural isotopic abundance using only milligram quantities of sample. This technique combines fast Magic Angle Spinning, low-power dipolar recoupling, and dynamic nuclear polarization with AsymPol biradicals as polarizing agents. These experiments are crucial for structural characterization as they provide information on short-and long-range distances. We showcase the effectiveness of this approach on various sample types, including polyglutamine fibrils involved in Huntington's disease and microcrystalline ampicillin, a small antibiotic molecule.