Studies of a chemically modified oligodeoxynucleotide containing a 5-atom amide backbone which exhibits improved binding to RNA

Chimeric oligodeoxyribonucleotides where the phosphodiester linkage -C3'-O- PO2--O-CH2-C4'- of DNA is substituted by the amide linkage -C3'-CH2-CH*(CH3 )-CO-NH-CH2-C4' (*either R or S stereochemistry) have been prepared and the ir binding to RNA targets have been investigated. Incorporation of a single amide unit increases the T-m by approximately 1.4-1.9 degreesC. Circular d ichroic spectra of these modified duplexes are similar to the wildtype DNA/ RNA.