Restoring symmetry in two-dimensional solid-state NMR correlation spectra

0009-2614/$ see front matter 2012 Elsevier B.V. A http://dx.doi.org/10.1016/j.cplett.2012.05.030 q First presented at the 53rd Rocky Mountain Con istry, August 2010, Snowmass, Colorado, USA. ⇑ Corresponding author at: Ecole Normale Supérie 24 rue Lhomond, 75231 Paris cedex 05, France. E-mail address: [email protected] (P. Tekely). The intrinsic asymmetry of 2D solid-state homonuclear NMR correlation spectra that arises from a nonuniform preparation of the magnetization can be removed by equilibrating the magnetization in the initial stage of the experiments through dipolar recoupling induced by PARIS or PARISxy schemes. Both methods ensure magnetization exchange with modest radio-frequency amplitudes and permit one to create an initial state that restores the symmetry about the main diagonal of 2D spectra of uniformly labeled biomolecules. This improves the determination of structural and kinetic information. Both recoupling schemes may also be used to record nearly quantitative peak amplitudes in 1D cross-polarization magic-angle-spinning spectra. 2012 Elsevier B.V. All rights reserved.