Chemical synthesis of a biologically active natural tRNA with its minor bases.

The complete chemical synthesis of an E. coli tRNA(Ala) with its specific minor nucleosides, dihydrouridine, ribothymidine and pseudouridine, is reported. The method makes use of protected 2'-O-tertiobutyldimethylsilyl-ribonucleoside-3'-O-(2-cyanoethyl-N- ethyl-N- methyl)phosphoramidites.

[Total chemical synthesis of natural transfer RNA].

New improvements in the chemical synthesis of oligoribonucleotides are reported and they are applied to the first total chemical synthesis of a natural RNA. This E. coli K12 alanine tRNA contains in its sequence dihydrouridine, ribothymidine and pseudo-uridine.

Incorporation by chemical synthesis and characterization of deoxyribosylformylamine into DNA.

2-deoxyribosylformylamine is a major oxidative DNA damage type which occurs upon the action of ionizing radiation on DNA. The protected 2-deoxyribosylformylamine phosphoramidite was synthesized and used in conjunction with previously reported alkali labile base protected phosphoramidites ('PAC phosphoramidites') for the preparation of oligodeoxyribonucleotides containing this lesion. Final deprotection of the oligonucleotides was performed under mild alkaline conditions to preserve the integrity of the fragile defect.

Structure and in vitro replication of DNA templates containing 7,8-dihydro-8-oxoadenine.

Adenine residues in DNA are oxidized under the action of ionizing radiation at the C-8 position to give 7,8-dihydro-8-oxoadenine. The formation of this lesion can be considered a cause of mutations and carcinogenesis. Oligodeoxyribonucleotides 39 and 47 bases long containing a single 7,8-dihydro-8-oxoadenine (8-hydroxyadenine) residue were synthesized by using nucleoside phosphoramidites.

Solid phase synthesis of the 5'-half of the initiator t-RNA from B. subtilis.

Using cyanoethyldiisopropylamino phosphoramidite chemistry, four oligonucleotides constituting a part of the sequence of the initiator t-RNA from B. subtilis were synthesized. For the protection of the exocyclic amino functions of bases, phenoxyacetyl group was used for adenine and guanine, and acetyl group was preferred for cytosine.