1. Prevalent sequences in the Human Genome Can Form Mini i-Motif Structures at Physiological pH
- Author
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Núria Escaja, Carlos González, Bartomeu Mir, Israel Serrano, Modesto Orozco, Diana Buitrago, and Universitat de Barcelona
- Subjects
0301 basic medicine ,Models, Molecular ,Stereochemistry ,Base pair ,Oligonucleotides ,Human chromosomes ,010402 general chemistry ,G-quadruplex ,01 natural sciences ,Biochemistry ,Genome ,Catalysis ,03 medical and health sciences ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,Human genetics ,Humans ,Repeated sequence ,Gene ,Base Pairing ,Repetitive Sequences, Nucleic Acid ,Cromosomes humans ,Genètica humana ,Base Sequence ,Chemistry ,Genome, Human ,Oligonucleòtids ,General Chemistry ,DNA ,Hydrogen-Ion Concentration ,3. Good health ,0104 chemical sciences ,G-Quadruplexes ,030104 developmental biology ,Nucleic acid ,Nucleic Acid Conformation ,Human genome - 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 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.