| Literature DB >> 6547530 |
T A Holak, P N Borer, G C Levy, J H van Boom, A H Wang.
Abstract
In 4M NaCl solutions (dC-dG)n (n = 3,4; approximately 9 mM) exist as a mixture o +/- B and Z forms. The low and high field components of two 31P NMR resonances originating from internal phosphodiester groups are assigned to the GpC and CpG linkages, respectively. Low temperatures stabilize the Z-forms, which completely disappear above 50 degrees C (n = 3) and 65 degrees C (n = 4). delta H = -44 and -17 kJ/mol for B to Z transition in the hexamer and octamer duplexes, respectively. Temperature dependent changes (0-50 degrees C range) in the spin-lattice relaxation times at 145.7 MHz are distinctly different for the 31P nuclei o +/- GpC and CpG groups. The relaxation data can be explained by assuming that the GpC phosphodiester groups undergo more local internal motion than do the CpG groups.Entities:
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Year: 1984 PMID： 6547530 PMCID： PMC318863 DOI： 10.1093/nar/12.11.4625
Source DB: PubMed Journal: Nucleic Acids Res ISSN： 0305-1048 Impact factor: 16.971