What is the structural difference between DNA and BNA

BNA 2’, 4’-BNANC [NMe] has a six-membered bridged ring structure with a unique structural feature, an N-O bond, which is a hydrophilic amino-oxy moiety, within the sugar moiety. A methyl group is attached to the nitrogen atom located in the bridge.

Oligonucleotides modified with this BNA have a very high affinity to RNA, are resistant to endonucleolytic cleavage by nucleases, and show a very low toxicity to hepatic cells.

The structure difference between a BNA and a DNA is shown in the image below: