ISSN:
0006-3525
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
We report the temperature dependence of the H2 and H8 purine ring proton resonances of oligoriboadenylates up to chain length 11, with or without a single guanosine residue at the 5′-end, second position, or 3′-end. The results suggest the following generalizations: (1) Stacking of the bases in a right-handed single-stranded helix is more extensive in the interior of the chain than at the chain ends. (2) The tendency of the terminal base to unstack is greater at the 5′-end than at the 3′-terminus. (3) G stacks more weakly than A, as evidenced by weak stacking of 3′-terminal G. Anomalies were also observed in the unstacking profile of G at the second position in the chain, indicating a conformational anomaly such as looping out of G, thereby allowing adjacent A's to stack together, or adoption by G of some other alternative structure. (4) The results imply that the environment at a given base is influenced by effects of longer range than nearest- or next-nearest-neighbor. Increasing ion condensation as chain length increases may be responsible for the slow approach of oligomer behavior to the properties of the high polymer.
Additional Material:
9 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/bip.360220313
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