In the double helix structure of DNA, the orientation of the sugar-phosphate backbone is characterized by specific angles between the sugars and the bases. This feature contributes to the overall helical structure of DNA. Which of the following correctly describes the orientation of the glycosidic bond in B-DNA?
1
Anti orientation of the glycosidic bond with respect to the sugar ring in purines and pyrimidines.
2
Syn orientation of the glycosidic bond with respect to the sugar ring in both purines and pyrimidines.
3
Anti orientation of the glycosidic bond with respect to the sugar ring in purines but syn in pyrimidines.
4
Syn orientation of the glycosidic bond with respect to the sugar ring in purines but anti in pyrimidines.