![]() A form of DNA is formed during crystallization step of X ray studies, as crystallization promotes dehydration forming A form. The existence of A form in live cells is not certain. The dehydrated environment allows them to open up thus widening the diameter of DNA. The hydrophobic nitrogen base pairs group together and tend to stay away from the aqueous environment. The sugar phosphate backbone is hydrophilic, and the interior part of helix i.e. The A form of DNA is formed in a dehydrated environment or in less than 75% humidity. Reason for the formation of A form of DNA: The major groves are deep and narrow minor groves are shallow and wide.The puckered sugar conformation is C3 endo type.The purine and pyrimidine are in anti-conformation at glycosyl bond.Both the strands are antiparallel in nature.It is right handed helix, and both the strands are held together by hydrogen bonds.Image courtesy: Quora The characteristics of A form of DNA are-: The major grooves are wide and deep minor groves are narrow and shallow.The puckered sugar conformation is C2’ endo type.The helix rise is 3.4 Å, it the distance along the helical axis between nucleotides.The both strands are hold together with Hydrogen bonds because of complementary relationship.The both the strands are antiparallel to each other, one runs from 5’ to 3’ and other runs from 3’ to 5’. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |