Abstract
The results of quantitative and systematic studies of the dependence of two-pulse spin-echo intensity on the pulse widths and of the Davies ENDOR response on the width of the preparation pulse, tp are reported. A formula that describes the Davies ENDOR response as a function of the selectivity parameter, ηη = Antp is presented. These measurements, which employ a variety of small molecules and metalloenzymes, not only provide information about the Davies ENDOR technique, but also give a quantitative description of the recently described POSHE method for hyperfine selection of heteronuclear pulsed ENDOR spectra through manipulation of pulse widths in the Davies ENDOR sequence. This procedure involves suppression of weakly coupled proton pattern and optimization of strongly coupled heteronuclei signals. It is demonstrated with single-crystal data for Cu(II)-doped Zn(glycinato)2 and frozen solution data for the blue copper protein Pseudomonas aeruginosa azurin.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 62-72 |
| Number of pages | 11 |
| Journal | Journal of Magnetic Resonance (1969) |
| Volume | 98 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jun 1 1992 |
Funding
We acknowledge the helpful discussions with and technical assistance of Dr. R. J. Gurbiel. This work has been supported by the National Institutes of Health (Grant HL 1353 I) and has received support from the National Science Foundation through Grant DMB 8807559 and the Materials Research Center of North-western University (Grant DMR-88 2 157 1). The equipment was purchased under a Grant DRR 04936 from the National Institutes of Health.