ISSN:
0006-3525
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The ratio of the spin-spin relaxation rate, R2, to the selective spin-lattice relaxation rate, R1s, can be used to detect and determine the magnitude of dipolar interactions between magnetically equivalent unclei in macromolecules. We use this method to show that there is strong interaction between adjacent AH2 protons in poly(dA) · poly(dT). The largest possible AH2-AH2 distance that will account for the observed magnitude of the interaction is ∼3.5 Å, provided the AH2 protons are located close (within 0.6 Å) to the helix axis. Structures with shorter AH2-AH2 separations could account for the nmr data, but they are rejected because they would reduce the interbase separation to unacceptably small values. A comparison of rates measured at 360 and 500 MHz shows that the chemical-shift anisotropy makes a negligible contribution to the observed relaxation rates.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/bip.360240705
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