Physics

Nucleic acid structure

Structural motif

Base pair

Biology

Gene

Sequence motif

Acoustics

Cytosine

Nucleic acid

Computational biology

Motif (music)

Genetics

Biochemistry

Nucleic Acids Research

The i-motif represents a paradigmatic example of the wide structural versatility of nucleic acids. In remarkable contrast to duplex DNA, i-motifs are four-stranded DNA structures held together by hemi- protonated and intercalated cytosine base pairs (C:C+). First observed 25 years ago, and considered by many as a mere structural oddity, interest in and discussion on the biological role of i-motifs have grown dramatically in recent years. In this review we focus on structural aspects of i-motif formation, the factors leading to its stabilization and recent studies describing the possible role of i-motifs in fundamental biological processes.

i-Motif DNA: structural features and significance to cell biology