Solid-state NMR study of the SH3 domain of α-spectrin:: application of 13C-15N TEDOR and REDOR

A fully C-13-N-15-labeled and a selectively alanine-C-13(beta) tryptophan-N-15(ring)-labeled sample of the Src homology region 3 (SH3) domain of alpha-spectrin (chicken), a 62 residue protein, were biosynthesized and studied by solid-state cross-polarization magic angle spinning (CP/MAS) NMR,C-13-N-15 rotational echo double resonance (REDOR) and N-15-C-13 transferred echo double resonance (TEDOR) spectroscopy. In the first part of the study it is shown that spectral editing with the TEDOR sequence leads to a drastic simplification of the C-13 MAS spectrum of the fully labeled sample, allowing the resolved spectroscopy of groups of C-13 nuclei, according to their distance to neighboring N-15 nuclei. In the second part of the study the inter-residual distance between the alanine residue Ala55 and the tryptophan residue Trp42 was determined by the measurement of the dipolar coupling between Ala-C-13(beta) and Trp-N-15(ring), yielding a dipolar coupling of 48 +/- 8 Hz, which after correction for fast molecular vibrations gives a value of 53 +/- 8 Hz, corresponding to a CN distance of 3.85 +/- 0.25 Hz. The result is compared to the CN distances obtained by x-ray diffraction and liquid-state NMR. Copyright (C) 2000 John Wiley & Sons, Ltd.