Accurate measurements of C-13-C-13 distances in uniformly C-13-labeled proteins using multi-dimensional four-oscillating field solid-state NMR spectroscopy

作者：Straaso Lasse Arnt; Nielsen Jakob Toudahl; Bjerring Morten; Khaneja Navin; Nielsen Niels Chr^*

来源：Journal of Chemical Physics, 2014, 141(11): 114201.

DOI：10.1063/1.4895527

Application of sets of C-13-C-13 internuclear distance restraints constitutes a typical key element in determining the structure of peptides and proteins by magic-angle-spinning solid-state NMR spectroscopy. Accurate measurements of the structurally highly important C-13-C-13 distances in uniformly C-13-labeled peptides and proteins, however, pose a big challenge due to the problem of dipolar truncation. Here, we present novel two-dimensional (2D) solid-state NMR experiments capable of extracting distances between carbonyl (C-13') and aliphatic (C-13(aliphatic)) spins with high accuracy. The method is based on an improved version of the four-oscillating field (FOLD) technique [L. A. Straaso, M. Bjerring, N. Khaneja, and N. C. Nielsen, J. Chem. Phys. 130, 225103 (2009)] which circumvents the problem of dipolar truncation, thereby offering a base for accurate extraction of internuclear distances in many-spin systems. The ability to extract reliable accurate distances is demonstrated using one-and two-dimensional variants of the FOLD experiment on uniformly C-13, N-15-labeled-L-isoleucine. In a more challenging biological application, FOLD 2D experiments are used to determine a large number of C-13'-C-13(aliphatic) distances in amyloid fibrils formed by the SNNFGAILSS fibrillating core of the human islet amyloid polypeptide with uniform C-13, N-15-labeling on the FGAIL fragment.

• 出版日期2014-9-21