Abstract
While both 31P and 113Cd are present at locations of interest in many different macromolecular systems, heteronuclear-detected relaxation measurements on these nuclei have been restrained by limitations in either resolution or signal-to-noise ratio. We have developed hetero TOCSY-based methods to overcome both of these problems. Two-dimensional versions of these experiments were utilized to measure 31P T1 and T2 values in DNA oligonucleotides; the additional resolution offered by a second dimension allowed determination of these values for most of the 31P resonances in a DNA dodecamer. The results from the experiments indicated that there was little significant variation in T1 values for the different phosphates in the DNA dodecamer; however, the T2 values showed a clear pattern, with lower values in the interior of the sequence than at the ends of the helix. Furthermore, a significant correlation between 31P chemical shifts and T2 values was observed. One-dimensional, frequency-selective versions of these experiments were also developed for use on systems containing a smaller number of heteronuclear spins. These methods were applied to investigate the heteronuclear relaxation properties of 113Cd in 113Cd2LAC9(61), a Cys6Zn2 DNA-binding domain. Data from the experiments confirm biochemical evidence that more significant differences occur in the metal-protein interactions between the two metal-binding sites than has been previously identified for proteins containing this motif.
Original language | English (US) |
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Pages (from-to) | 180-188 |
Number of pages | 9 |
Journal | Journal of biomolecular NMR |
Volume | 6 |
Issue number | 2 |
DOIs | |
State | Published - Sep 1995 |
Keywords
- Cadmium
- Cytosine arabinoside
- DNA
- Hetero TOCSY
- Heteronuclear
- LAC9
- Phosphorus
- Relaxation
ASJC Scopus subject areas
- Biochemistry
- Spectroscopy