Cruciform sites

Figure 17. Probing DNA cruciforms (88). Shown on the left is tris(diphenylphenanthroline)-rhodium(III), [Rh(DIP),] , which cleaves DNA cruciforms in a double-stranded fashion with photoactivation. On the right are shown the major cleavage sites for [Rh(DIP),] (delineated by the arrows) on a pBR322 cruciform.

All specimens display heavy corrosion at the fault site in the lower region of the cruciform injury site, they show formation of rust smears which tend to spread in the direction of the current caused by the stirrer. 

The primer was tested on one plate without top coat (with a cruciform injury site), and on another with top coat (with scratch damage). 

Hairpins can form when there are complementary sequences within the same strand but separated by a noncomplementaiy region, such as the sequence 5 -CGCGCGCGAAAGCGCGCG-3 where the central GAAA forms the loop and the imderlined bases at the termini form the stem (Fig. 5). If a hairpin is formed within the context of double-stranded DNA, the complementary strand can also fold into a hairpin, yielding a cruciform structin-e, or remain impaired. Such structures likely serve as binding sites for proteins. Fimthermore, the hairpin motif is one of the most common secondary structin-e elements observed in RNA (17). 

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