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Title: Multinuclear NMR studies of DNA hairpins. 1. Structure and dynamics of d(CGCGTTGTTCGCG)

Journal Article · · Biochemistry; (USA)
DOI:https://doi.org/10.1021/bi00433a012· OSTI ID:5605651

The solution structure of the hairpin formed by d(CGCGTTGTTCGCG) has been examined in detail by a wide variety of NMR techniques. The hairpin was characterized by proton NMR to obtain interproton distances and torsion angle information. An energy-minimized model was constructed that is consistent with these data. The hairpin consists of a B-DNA stem of four C-G base pairs and a loop region consisting of five unpaired bases. Three bases in the 5' of the loop are stacked over the 3' end of the stem, and the other two bases in the 3' of the loop are stacked over the 5' end of the stem. The phosphorus NMR spectrum revealed a phosphate in the stem region with an unusual conformation, and two phosphates, P{sub 9} and P{sub 10}, were found to undergo intermediate exchange between conformations. The hairpin was also synthesized with a carbon-13 label in each of the thymidine C6 carbons, and relaxation measurements were performed to determine the extend of internal motions in the loop region. The loop base are more flexible than the stem bases and exhibit subnanosecond motions with an amplitude corresponding to diffusion in a cone of {approximately} 30{degree}.

OSTI ID:
5605651
Journal Information:
Biochemistry; (USA), Vol. 28:7; ISSN 0006-2960
Country of Publication:
United States
Language:
English