Open AccessCrystal structure of an antiparallel DNA fragment with Hoogsteen base pairing
Author(s) -
Nicola G. A. Abrescia,
Andrew W. Thompson,
Tam HuynhDinh,
Juan A. Subirana
Publication year - 2002
Publication title -
proceedings of the national academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.052675499
Subject(s) - antiparallel (mathematics) , base pair , dna , duplex (building) , crystallography , pairing , crystal structure , helix (gastropod) , triple helix , molecule , chemistry , stereochemistry , biology , genetics , physics , magnetic field , ecology , quantum mechanics , snail , superconductivity , organic chemistry
We report here an alternative double-helical structure of the DNA molecule. It has been found in the d(ATA(Br)UAT) and d(ATATAT) sequences by single-crystal x-ray crystallography. This sequence is found not only in TATA boxes, but also in other regulatory regions of DNA. Bases of the two antiparallel strands form Hoogsteen pairs, with adenines in the syn conformation. The structure is related neither to those found in triple helices nor to parallel DNA duplexes. Its conformational parameters are very similar to those of duplex DNA in the B form. Both forms may coexist under physiological conditions, although the Hoogsteen pairing greatly influences the recognition sites on DNA. Our results demonstrate that an alternative to the classical B-DNA double helix is possible.
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