Open AccessAn intercalation-locked parallel-stranded DNA tetraplex
Author(s) -
Shailesh Tripathi,
Daoning Zhang,
Paul J. Paukstelis
Publication year - 2015
Publication title -
nucleic acids research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 9.008
H-Index - 537
eISSN - 1362-4954
pISSN - 0305-1048
DOI - 10.1093/nar/gkv033
Subject(s) - intercalation (chemistry) , oligonucleotide , dna , duplex (building) , base pair , nucleic acid thermodynamics , biology , nucleotide , crystallography , nucleic acid denaturation , molecular structure of nucleic acids: a structure for deoxyribose nucleic acid , stereochemistry , biochemistry , base sequence , chemistry , gene , inorganic chemistry
DNA has proved to be an excellent material for nanoscale construction because complementary DNA duplexes are programmable and structurally predictable. However, in the absence of Watson-Crick pairings, DNA can be structurally more diverse. Here, we describe the crystal structures of d(ACTCGGATGAT) and the brominated derivative, d(AC(Br)UCGGA(Br)UGAT). These oligonucleotides form parallel-stranded duplexes with a crystallographically equivalent strand, resulting in the first examples of DNA crystal structures that contains four different symmetric homo base pairs. Two of the parallel-stranded duplexes are coaxially stacked in opposite directions and locked together to form a tetraplex through intercalation of the 5'-most A-A base pairs between adjacent G-G pairs in the partner duplex. The intercalation region is a new type of DNA tertiary structural motif with similarities to the i-motif. (1)H-(1)H nuclear magnetic resonance and native gel electrophoresis confirmed the formation of a parallel-stranded duplex in solution. Finally, we modified specific nucleotide positions and added d(GAY) motifs to oligonucleotides and were readily able to obtain similar crystals. This suggests that this parallel-stranded DNA structure may be useful in the rational design of DNA crystals and nanostructures.