The secondary structure of DNA is important in many events in cellular life. Replication, transcription and regulation of expression of many genes depends on local differences or changes in DNA structure. Recombination which leads to rearrangement of genes takes advantage of the ability to form an unusual structure called a Holliday’s structure. Also different kinds of mutations occur as a result of specific DNA structure.
Many mechanisms such as activation and inhibition of expression numerous genes, methylation and cleavages of DNA at the base have the ability of proteins to recognise well defined regions of DNA and one of the ways is recognition the local differences in secondary structure (excitase in a complex with A-DNA as jpg file or pdb file).
