A bifurcated hydrogen-bonded conformation in the d(A.T) base pairs of the DNA dodecamer d(CGCAAATTTGCG) and its complex with distamycin.

M. Coll, C. A. Frederick, A. H. Wang, A. Rich

研究成果: 雜誌貢獻文章同行評審

731 引文 斯高帕斯(Scopus)

摘要

The crystal structures of d(CGCA3T3GCG) complex to the antitumor drug distamycin and the DNA fragment alone were solved by x-ray diffraction at 2.2 and 2.5 A resolution, respectively. The drug lies in the narrow minor groove near the center of the B-DNA fragment covering 5 of the 6 A.T base pairs. It is bound to the DNA by hydrogen bonding, van der Waals, and electrostatic interactions. In addition, the DNA was found to have an unusual conformation in the (dA)3.(dT)3 regions. These base pairs have a high positive propeller twist so that in the major groove the adenine amino group is located intermediate between the carbonyl O-4 groups of two adjacent thymines of the opposite strand, making bifurcated hydrogen bonds to the two thymine residues. This suggests a model to explain the unusual properties of poly-(dA).poly(dT) in which a modified B conformation is associated with a large propeller twist of the bases and a set of continuous bifurcating hydrogen bonds along the major groove, which may provide incremental stability to these segments. In addition, shorter segments of (dA)3-6.(dT)3-6 may have this conformation in the midst of B-DNA and stabilize bends in the DNA that may be associated with stacking on one of the high propeller-twisted bases at the ends of these segments.

原文英語
頁(從 - 到)8385-8389
頁數5
期刊Proceedings of the National Academy of Sciences of the United States of America
84
發行號23
DOIs
出版狀態已發佈 - 12月 1987
對外發佈

ASJC Scopus subject areas

  • 多學科

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