DNA forms a double helix. But why was that rotated? Could the two chains just be parallel to each other? What is the exact reason for this spatial form?
Answer
Each DNA strand is made up of 4 different nucleotides. These building blocks are themselves made up of a phosphate group, a deoxyribose sugar and a nucleobase. The nucleobase determines the type of nucleotide. DNA contains the nucleobases adenine, guanine, cytosine and thymine.
The structure of a single DNA strand is determined by a ‘backbone’ of alternating phosphate groups and deoxyribose sugars. These sugars have a certain asymmetry (https://nl.wikipedia.org/wiki/Deoxyribose). They are also said to be D sugars. Due to this asymmetry, the bonds to the adjacent phosphate groups will not align and the DNA strand will therefore have a twisted structure as a whole.
The ‘favourite’ form of a DNA strand is the helix structure. However, a more irregular shape can also occur. The complete straightening of the chain is the subject of research. This could be useful, for example, to determine the sequence of the DNA bases (= the DNA code). (https://blogs.plos.org/everyone/2013/09/23/dna-funtime-how-to-stretch-dna-and-put-it-anywhere-you-want-sort-of/)
Answered by
Tom Lebacq
Old Market 13 3000 Leuven
https://www.kuleuven.be/
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