Prevalent Sequences in the Human Genome Can Form Mini i-Motif Structures at Physiological pH.
Mir, B., Serrano, I., Buitrago, D., Orozco, M., Escaja, N., Gonzalez, C.(2017) J Am Chem Soc 139: 13985-13988
- PubMed: 28933543 
- DOI: https://doi.org/10.1021/jacs.7b07383
- Primary Citation of Related Structures:  
5OGA - PubMed Abstract: 
We report here the solution structure of several repetitive DNA sequences containing d(TCGTTCCGT) and related repeats. At physiological pH, these sequences fold into i-motif like quadruplexes in which every two repeats a globular structure is stabilized by two hemiprotonated C:C + base pairs, flanked by two minor groove tetrads resulting from the association of G:C or G:T base pairs. The interaction between the minor groove tetrads and the nearby C:C + base pairs affords a strong stabilization, which results in effective pH T values above 7.5. Longer sequences with more than two repeats are able to fold in tandem, forming a rosary bead-like structure. Bioinformatics analysis shows that these sequences are prevalent in the human genome, and are present in development-related genes.
Organizational Affiliation: 
Inorganic and Organic Chemistry Department, Organic Chemistry Section, and IBUB, University of Barcelona , Martí i Franquès 1-11, 08028 Barcelona, Spain.