A new oligonucleotide analog, bicyclo[3.2.1]-amide-DNA was synthesized. A h
omo-adenylate sequence of this analog, efficiently forms hetero-duplexes wi
th complementary natural DNA and RNA. The corresponding homo-thymidylate se
quence, however, does not base-pair to complementary DNA and RNA, but forms
a stable duplex with the homo-adenylate oligomer of the same backbone type
. The structure of this duplex is virtually enantiomeric to that of a natur
al B-DNA, as inferred from CD-spectroscopy.