Results of characterization of short DNA using nuclear magnetic resonance are described. Nuclear magnetic resonance studies indicate that double stranded DNA is not a static structure. Many types of internal motions are present within the DNA chain, some being strongly coupled, while others are uncoupled or coupled. The coupled motions probably produce wave-like motions observed at low DNA concentrations. The uncoupled motions are more localized, reflecting the pseudorotational qualities of the deoxyribose ring. The sugar carbons C2' and C5' behave in a unique manner, with some motions of C2' being completely uncoupled from other internal DNA motions, while the motions of C5' are highly coupled. These results suggest a possible concentration dependent change in configuration of the sugar ring from C2' endo to C3' endo, where some of the internal motions of the sugar ring are uncoupled from motions of the DNA backbone. A model of conic diffusion superimposed on axially symetric rotation suggests that the rotational correlation times for the internal motions of double stranded DNA are approximately four nanseconds. Solutions of short DNA chains become ordered at high concentrations in a highly cooperative manner, with the critical concentration being inversely related to the chain length. NMR resonance intensities are greatly reduced above the phase transition. NMR resonances are also repressed for long DNA when compared with those of 147 np at the similar concentrations below the phase transition. These results suggest that any inability to observe ('13)C NMR resonances from double stranded DNA is due to local interchain interactions which "freeze out" the coupled internal motions. The internal motions of the carbons are greatly restricted when the DNA is incorporated into nucleosome core particles. However, the motions of the DNA phosphates are not greatly / affected. The ability to obtain ('13)C NMR spectra from short double stranded DNA allows for a wide range of new experiments such as studies of DNA-environmental interactions. / Source: Dissertation Abstracts International, Volume: 43-04, Section: B, page: 1076. / Thesis (Ph.D.)--The Florida State University, 1982.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_74818 |
| Contributors | HILLIARD, PETER ROSE, JR., Florida State University |
| Source Sets | Florida State University |
| Detected Language | English |
| Type | Text |
| Format | 326 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
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