Black vertical lines represents interstrand binding between complementary strands, while the gray concentric lines denote the intrastrand complementary nature of the bases in the inverted repeat. Inverted repeats can form hairpin structures. An inverted repeat drawn as a hairpin structure. This can occur in both strands of complementary DNA forming a cruciform structure. B. A more realistic illustration of the hairpin structure illustrating the twist.
Gray letters indicate the sequence is behind the overlying black sequence.
C. Crystal structure of the inverted repeat plotted using RasMac Molecular Graphic Macintosh Version 2.6 and clearly shows the unpaired loop at the top of the hairpin structure.