title: Asynchronous through-bond homonuclear isotropic mixing: application to carbon-carbon transfer in perdeuterated proteins under MAS.
abstract: Multiple-bond carbon-carbon homonuclear mixing is a hurdle in extensively deuterated proteins and under fast MAS due to the absence of an effective proton dipolar-coupling network. Such conditions are now commonly employed in solid-state NMR spectroscopy. Here, we introduce an isotropic homonuclear (13)C-(13)C through-bond mixing sequence, MOCCA, for the solid state. Even though applied under MAS, this scheme performs without rotor synchronization and thus does not pose the usual hurdles in terms of power dissipation for fast spinning. We compare its performance with existing homonuclear (13)C-(13)C mixing schemes using a perdeuterated and partially proton-backexchanged protein. Based on the analysis of side chain carbon-carbon correlations, we show that particularly MOCCA with standard 180-degree pulses and delays leading to non-rotor-synchronized spacing performs exceptionally well. This method provides high magnetization transfer efficiency for multiple-bond transfer in the aliphatic region compared with other tested mixing sequences. In addition, we show that this sequence can also be tailor-made for recoupling within a selected spectral region using band-selective pulses.
authors: Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, 37077, Göttingen, Germany.
authors: Natalia
authors: N
authors: Kulminskaya
authors: Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, 37077, Göttingen, Germany.
authors: Suresh Kumar
authors: SK
authors: Vasa
authors: Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, 37077, Göttingen, Germany.
authors: Karin
authors: K
authors: Giller
authors: Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, 37077, Göttingen, Germany.
authors: Stefan
authors: S
authors: Becker
authors: Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, 37077, Göttingen, Germany. rali@nmr.mpibpc.mpg.de.
authors: Rasmus
authors: R
authors: Linser
mesh_terms: D002244:Carbon / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D019906:Nuclear Magnetic Resonance, Biomolecular; D011506:Proteins / Q000737:chemistry*; D013049:Spectrin / Q000737:chemistry
chemical_list: D011506:Proteins; D013049:Spectrin; D002244:Carbon
keywords: Homonuclear isotropic mixing; MAS; MOCCA; Perdeuterated proteins; SH3 domain; Solid-state NMR (ssNMR)