@article {428, title = {Application of rotational resonance to inhomogeneously broadened systems}, journal = {Chemical Physics Letters}, volume = {251}, year = {1996}, note = {Chem Phys LettUd924Times Cited:17Cited References Count:28}, month = {Mar 22}, pages = {223-229}, abstract = {

A protocol is presented for the determination of internuclear distances using rotational-resonance magnetization-exchange NMR in systems with inhomogeneously broadened lines. Non-linear least-square fitting procedures are used to obtain the distance, the inhomogeneous broadening, the zero-quantum relaxation time, and error estimates for these parameters. We apply this procedure to a biological system of unknown structure.

}, keywords = {nmr}, isbn = {0009-2614}, doi = {Doi 10.1016/0009-2614(96)00098-X}, url = {://WOS:A1996UD92400015}, author = {Heller, J. and Larsen, R. and Ernst, M. and Kolbert, A. C. and Baldwin, M. and Prusiner, S. B. and Wemmer, D. E. and Pines, A.} } @article {429, title = {Solid-state NMR studies of the prion protein H1 fragment}, journal = {Protein Science}, volume = {5}, year = {1996}, note = {Protein SciVa138Times Cited:74Cited References Count:53}, month = {Aug}, pages = {1655-1661}, abstract = {

Conformational changes in the prion protein (PrP) seem to be responsible for prion diseases. We have used conformation-dependent chemical-shift measurements and rotational-resonance distance measurements to analyze the conformation of solid-state peptides lacking long-range order, corresponding to a region of PrP designated H1. This region is predicted to undergo a transformation of secondary structure in generating the infectious form of the protein. Solid-state NMR spectra of specifically C-13-enrrched samples of H1, residues 109-122 (MKHMAGAAAAGAVV) of Syrian hamster PrP, have been acquired under cross-polarization and magic-angle spinning conditions. Samples lyophilized from 50\% acetonitrile/50\% water show chemical shifts characteristic of a beta-sheet conformation in the region corresponding to residues 112-121, whereas samples lyophilized from hexafluoroisopropanol display shifts indicative of alpha-helical secondary structure in the region corresponding to residues 113-117. Complete conversion to the helical conformation was not observed and conversion from alpha-helix back to beta-sheet, as inferred from the solid-state NMR spectra, occurred when samples were exposed to water. Rotational-resonance experiments were performed on seven doubly C-13-labeled H1 samples dried from water. Measured distances suggest that the peptide is in an extended, possibly beta-strand, conformation. These results are consistent with the experimental observation that PrP can exist in different conformational states and with structural predictions based on biological data and theoretical modeling that suggest that H1 may play a key role in the conformational transition involved in the development of prion diseases.

}, keywords = {alpha-helices}, isbn = {0961-8368}, url = {://WOS:A1996VA13800019}, author = {Heller, J. and Kolbert, A. C. and Larsen, R. and Ernst, M. and Bekker, T. and Baldwin, M. and Prusiner, S. B. and Pines, A. and Wemmer, D. E.} } @article {463, title = {Measurement of Internuclear Distances by Switched Angle Spinning Nmr}, journal = {Journal of Physical Chemistry}, volume = {98}, year = {1994}, note = {J Phys Chem-UsPc619Times Cited:11Cited References Count:20}, month = {Aug 18}, pages = {7936-7938}, abstract = {

Dipolar switched angle spinning, an NMR technique due to Terao et al. [Terao, T.; Miura H.; Saika, A, J. Chem. Phys. 1986, 85, 3816], has been used to measure C-13-C-13 distances in the solid state. The experiment involves rotation of the sample at two different angles during different periods of a two-dimensional experiment. An evolution period with off-magic-angle spinning and chemical shift refocusing, followed by detection of the signal under magic angle spinning, yields scaled Pake patterns in omega(1), correlated with their isotropic shifts in omega(2) allowing the high-resolution measurement of dipolar couplings. We demonstrate this experiment on samples of doubly C-13 labeled zinc acetate and a 14 amino acid peptide, in which we show that under optimal conditions distances of up to 5 Angstrom may be measured.

}, keywords = {protein}, isbn = {0022-3654}, doi = {Doi 10.1021/J100084a003}, url = {://WOS:A1994PC61900003}, author = {Kolbert, A. C. and Grandinetti, P. J. and Baldwin, M. and Prusiner, S. B. and Pines, A.} }