Total synthesis of the structural gene for the precursor of a tyrosine suppressor transfer RNA from Escherichia coli. 2. Chemical synthesis of the deoxypolynucleotide segments corresponding to the nucleotide sequence 1-31.

Chemical synthesis of the undecanucleotides d(T-G-G-G-G-G-A-A-G-G-A), d(C-C-C-C-A-C-C-A-C-C-A), and d(T-C-G-A-A-T-C-C-T-T-C), and the nonanucleotides, d(T-T-C-G-A-A-C-C-T) and d(T-T-C-G-A-A-G-G-T) are described. The deoxyribopolynucleotides together represent the DNA duplex corresponding to the nucleotide sequence 1-31 (from the 3'-end) of the gene for the tyrosine suppressor tRNA. The synthesis, which basically used the previously developed chemical methods, started with 5' and N-protected deoxyribonucleosides. Successive condensations at the 3'-end were performed using suitably protected mononucleotides or preformed di- and trinucleotides. The condensing agents used were mesitylenesulfonyl chloride or triisopropyl benzenesulfonyl chloride. The required condensation products were isolated partly by solvent partition methods or, in the case of longer chains, by anion exchange chromatography. The completely deprotected deoxypolynucleotides were further purified by anion exchange chromatography in the presence of 7 M urea and characterized by chemical and enzymatic methods.