i-motif DNA structure, illustration. The intercalated motif (i-motif) structure is a four stranded knot of DNA (deoxyribonucleic acid) that forms in cytosine-rich regions of a DNA molecule. Cytosine is one of the four nucleotide bases of DNA. When forming a double helix, cytosine bonds only with guanine. However, in i-motif structures two cytosine bases bond to each other. i-motif structures are thought to have a regulatory role in the genome.