title: Optimal (2)H rf Pulses and (2)H-(13)C Cross-Polarization Methods for Solid-State (2)H MAS NMR of Perdeuterated Proteins.
abstract: We present a novel concept for rf pulses and optimal control designed cross-polarization experiments for quadrupolar nuclei. The methods are demonstrated for (2)H CP-MAS and (2)H multiple-pulse NMR of perdeuterated proteins, for which sensitivity enhancements up to an order of magnitude are presented relative to commonly used approaches. The so-called RESPIRATION rf pulses combines the concept of short broad-band pulses with generation of pulses with large flip angles through distribution of the rf pulse over several rotor echoes. This lead to close-to-ideal rf pulses, facilitating implementation of experiments relying on the ability to realize high-performance 90 and 180° pulses, as, for example, in refocused INEPT and double-to-single quantum coherence experiments, or just pulses that provide a true representation of the quadrupolar powder pattern to extract information about the structure or dynamics. The optimal control (2)H → (13)C CP-MAS method demonstrates transfer efficiencies up to around 85% while being extremely robust toward rf inhomogeneity and resonance offsets.
authors: †Center for Insoluble Protein Structures (inSPIN), Interdisciplinary Nanoscience Center (iNANO) and Department of Chemistry, Aarhus University, DK-8000 Aarhus C, Denmark.|‡Shanghai Key Lab Magnetic Resonance, East China Normal University, Shanghai 200062, Peoples Republic China.
authors: Daxiu
authors: D
authors: Wei
authors: §NMR Supported Structural Biology, Leibniz-Institut für Molekulare Pharmakologie (FMP), Robert Roessle Strasse 10, D-13125 Berlin, Germany.
authors: Ümit
authors: Ü
authors: Akbey
authors: †Center for Insoluble Protein Structures (inSPIN), Interdisciplinary Nanoscience Center (iNANO) and Department of Chemistry, Aarhus University, DK-8000 Aarhus C, Denmark.
authors: Berit
authors: B
authors: Paaske
authors: §NMR Supported Structural Biology, Leibniz-Institut für Molekulare Pharmakologie (FMP), Robert Roessle Strasse 10, D-13125 Berlin, Germany.
authors: Hartmut
authors: H
authors: Oschkinat
authors: §NMR Supported Structural Biology, Leibniz-Institut für Molekulare Pharmakologie (FMP), Robert Roessle Strasse 10, D-13125 Berlin, Germany.|⊥Center for Integrated Protein Science Munich (CIPS-M) at Department of Chemistry, Technische Universität München, Lichtenbergstrasse 4, D-85747 Garching, Germany, and Helmholtz-Zentrum München, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany.
authors: Bernd
authors: B
authors: Reif
authors: †Center for Insoluble Protein Structures (inSPIN), Interdisciplinary Nanoscience Center (iNANO) and Department of Chemistry, Aarhus University, DK-8000 Aarhus C, Denmark.
authors: Morten
authors: M
authors: Bjerring
authors: †Center for Insoluble Protein Structures (inSPIN), Interdisciplinary Nanoscience Center (iNANO) and Department of Chemistry, Aarhus University, DK-8000 Aarhus C, Denmark.
authors: Niels Chr
authors: NC
authors: Nielsen
keywords: 2H MAS; CP; optimal control; optimal rf pulses; proteins; sensitivity enhancement; solid-state NMR